Real accruals based accounting

It is my understanding that in the accrual based accounting reports are based on the invoice dates of the sale- and purchase invoices. However, it often occurs that invoice date does not match the month in which the actual work was performed/services rendered, g.e. work performed in September invoiced in October. I would have expected a field in sale- & purchase invoices in which you can insert the date or week number in which the work was actually performed per line item and that the reporting module can generate P&L reports based on these fields. Does anyone have an idea on how the above described can be achieved within

Depending on the accounting standards under which you operate, income is recognized when a critical event has occurred establishing that the customer owes you the money, the amount of that obligation can be fairly determined, and payment of the obligation is reasonably assured. Under most credit sale situations, payment is not assured until a sales invoice is raised. So recognizing income in the month when the invoice is raised is correct. But until then, work in progress can be both an asset and accrued income

In Manager, billable work can be tracked with the Billable Time module. Invoices for billable time will show the date of the work. Billable time recorded appears in both the Billable time asset account and Billable time - movement income account. When the time is invoiced, the amount in Billable time is transferred to Accounts receivable and the amount in Billable time - movement is transferred to Billable time - invoiced. So the P&L is always fully current. See these Guides:

For billable work not tracked in the Billable Time tab, you should raise sales invoices during the accounting period for which you want the income to show on your P&L. In other words, invoice for September work during September. Otherwise, both your balance sheet and P&L lag your position and performance.