Customer Payment Allocation

Hello again.
Business is a trucking service who makes fuel withdrawals from its Customer charged against trucking services rendered. Various individual invoices were recorded for each trucking service rendered and for each fuel withdrawn. Customer pays its account deducting thereof fuel withdrawals. How can I lump the payment for the trucking services and the fuel withdrawn.
Example: 20 individual transactions for trucking service recorded totalling P100,000 and 25 individual transactions for fuel withdrawals chargeable against trucking billing totalling P68,000. Customer paid P80,000 and deducted P50,000 for fuels withdrawn. How can I apply the payment of P80,000 in lump (instead of individually applying it per sales invoice) and the deduction of P50,000 in lump also (instead of individually applying it per purchase invoice? This is to avoid repetitive procedure/process and for ease of audit trail. What is your suggestion? Thank you.

Read the Guide on simultaneous supplier and customer: Use a journal entry.

Noted. Thank you.