Is it permissible to record sales exceeding the monthly "target" in the following month, knowing that exceeding the current target leads to an increase in the subsequent month, which affects incentives?

You must adhere to the terms of the contract and record sales each month in its respective month, because violating this involves lying and breaching the agreed-upon terms, and perhaps falling into consuming wealth unjustly. It is advisable to explain any harm to the company owners and try to reach an agreement with them that guarantees the rights of both parties.