How such a situation may arise is when you know what you’ve delivered and you recognize revenue based on that, however, not all invoices from your suppliers, subcontractors etc. have reached you.

What to do in such a situation? 

Something I have come across and that could also help you is recognizing expenses based on the expected gross margin you’ve set for your service or for the project itself. If you know that the expenses are mostly in line with the budget and there are no major deviations, you can expect for the gross profit to be as you projected it. If you didn’t do it, which is you don’t know what your expected gross profit shall be from the project I would say it’s not smart way to run a business.

So, you know your sales and you know your expected gross margin. Multiplying the revenue with the gross margin (in the form of a per cent), you get the gross profit. Now taking this profit off from the revenues you’ve recognized you’ll reach to the expenses relating to revenues in the reporting period.

As it is, in accrual basis accounting you ought to recognize revenues and related expenses in the same period and as such, the above mentioned method enables you to do just that.