Project Billing - WIP Management is where ERP discipline either begins or breaks.
Work-in-Progress (WIP) Tracking, Aging, and Write-Off looks operational from far away. In a real finance team, it is a chain of assertions: the right actor started the work, the required records existed, the control policy was applied, the state change was preserved, and the outcome can be explained later without rebuilding the transaction from emails and spreadsheets.
The expected business outcome is specific: WIP aging report available daily; WIP older than 60 days escalated automatically; write-offs approved within three business days of request.
The control flow a finance team actually needs.
Step 1
WIP Aging Buckets: Current, 30, 60, 90,...
Step 2
WIP Balance Ties To Approved Timesheet...
Step 3
WIP Transfer To Invoice Is Full Or Partial
Step 4
Write-Off Requires Dual Approval Above...
Step 5
Write-Off Posts To Configurable GL Account
The ERP surface involved.
Module
Project Billing - WIP Management
Actors
Billing Manager, Finance Controller, Project Manager
Tier
Tier 1
Finance area
Project & Service Management (PSA) and Revenue Recognition
Region lens
US and UK finance teams
Publication date
June 9, 2026
WIP aging buckets: current, 30, 60, 90, 90+ days; WIP balance ties to approved timesheet and expense entries at line level; WIP transfer to invoice is full or partial; write-off requires dual approval above configurable threshold; write-off posts to configurable GL account; WIP balance by project, client, and partner visible in real-time; WIP reconciliation report ties to AR subledger; automated alerts for WIP exceeding age or value thresholds.
US and UK teams have different compliance hooks, but the same control problem.
US teams usually care about clean evidence for audit support, vendor records, payment controls, tax reporting, and management review. UK teams usually care about VAT-ready records, approval evidence, digital-record discipline, and traceable postings. The country-specific details differ, but the operating pattern is the same: the ERP needs controlled records, explicit ownership, defensible state changes, and evidence that survives beyond the person who completed the task.
The control matrix.
| Control area | Requirement | Acceptance proof |
|---|---|---|
| Control 1 | WIP aging buckets: current, 30, 60, 90, 90+ days | Given approved timesheet and expense entries accumulating WIP by project |
| Control 2 | WIP balance ties to approved timesheet and expense entries at line level | when billing cycle runs and unbillable or aged WIP requires write-off |
| Control 3 | WIP transfer to invoice is full or partial | then WIP transfers to invoice on billing, write-off requires dual approval above threshold, is posted to the configured GL write-off account, and the WIP aging report reflects the change |
| Control 4 | write-off requires dual approval above configurable threshold | negative) when a write-off above the threshold is attempted with single approval then the system rejects with 403 and error code DUAL_APPROVAL_REQUIRED. |
| Control 5 | write-off posts to configurable GL account | WIP aging report available daily; WIP older than 60 days escalated automatically; write-offs approved within three business days of request. |
| Control 6 | WIP balance by project, client, and partner visible in real-time | WIP aging report available daily; WIP older than 60 days escalated automatically; write-offs approved within three business days of request. |
Audit evidence is a chain, not a folder.
| Evidence layer | What should be preserved |
|---|---|
| Business event | As consultants log approved time and expenses, the ERP accumulates WIP balances by project and client. The billing manager reviews a WIP aging report each week, identifying balances older than 30 days. Unbilled WIP is transferred to invoices on billing cycle dates. WIP balances deemed unrecoverable (scope disputes, client insolvency) are written off through an approval workflow, with the write-off posted to a bad debt or write-off expense account and removed from WIP. |
| Control rules | WIP aging buckets: current, 30, 60, 90, 90+ days; WIP balance ties to approved timesheet and expense entries at line level; WIP transfer to invoice is full or partial; write-off requires dual approval above configurable threshold; write-off posts to configurable GL account; WIP balance by project, client, and partner visible in real-time; WIP reconciliation report ties to AR subledger; automated alerts for WIP exceeding age or value thresholds. |
| Acceptance proof | Given approved timesheet and expense entries accumulating WIP by project; when billing cycle runs and unbillable or aged WIP requires write-off; then WIP transfers to invoice on billing, write-off requires dual approval above threshold, is posted to the configured GL write-off account, and the WIP aging report reflects the change; (negative) when a write-off above the threshold is attempted with single approval then the system rejects with 403 and error code DUAL_APPROVAL_REQUIRED. |
| Data record | |
| System event | |
| Lifecycle state | |
The useful version of this workflow is not only fast. It is inspectable. A controller, auditor, or operator should be able to move from source event to system record to state transition to final business outcome without guessing.
Implementation contracts.
Reference data model
`wip_entry` { external_id: string, project_id: string, client_id: string, source_type: enum(TIMESHEET,EXPENSE), source_id: string, amount_minor: int64, currency_code: char(3), entry_date: date, status: enum(UNBILLED,BILLED,WRITTEN_OFF) }; `wip_writeoff` { external_id: string, wip_entry_ids: []string, amount_minor: int64, currency_code: char(3), approved_by_primary: string, approved_by_secondary: string, gl_account_id: string, status: enum(PENDING,APPROVED,POSTED) }; (reference, product may differ).API and events
`POST /v1/wip-writeoffs` { external_id, wip_entry_ids, amount_minor, currency_code, reason } -> 201 { writeoff_id }; `POST /v1/wip-writeoffs/{id}/approve` { approver_level: enum(PRIMARY,SECONDARY) } -> 200; `POST /v1/wip-writeoffs/{id}/post` -> 201 { journal_entry_id }; `GET /v1/projects/{id}/wip-aging` { buckets: [30,60,90] }; emits `wip.written_off` event; idempotent via `external_id`.State transitions
`UNBILLED -> BILLED` (invoice transfer) or `UNBILLED -> WRITTEN_OFF` (write-off); terminal states are BILLED and WRITTEN_OFF; guard: WRITTEN_OFF requires both PRIMARY and SECONDARY approvals when above threshold; BILLED entries cannot be written off without invoice void first.Common implementation traps.
Treating the workflow as data entry
If the ERP only stores the final record, the team loses the decision trail that explains how the record became valid.
Hiding exception logic
Exceptions need owners, reason codes, and time stamps. A vague pending state is not a control.
Posting without recovery design
Retries, duplicate submissions, and partial failures must be explicit so the system does not create inconsistent records.
Skipping evidence design
A workflow that cannot produce evidence on demand will eventually push finance teams back into manual screenshots and spreadsheets.
Where Rivane fits.
Rivane is built for finance workflows where automation must stay tied to source documents, approvals, state transitions, ledger impact, reporting, and audit evidence. Use this guide as a checklist for evaluating whether an ERP workflow is merely digitized or actually controlled.
References and source basis.
These sources provide the standards, regulatory, or government context around the flow. They are included so the guide is useful to finance operators, auditors, and implementation teams, not only buyers reading software copy.