If you have a customer who is also a supplier, you may want to offset the outstanding customer and supplier invoices. This is known as making a contra entry.
In MYBOS, all sales invoices are sub-accounts of Accounts receivable while purchase invoices are sub-accounts of Accounts payable. This means you can easily credit sales invoice and debit purchase invoice using journal entries.
For example, you have a customer who owes you 1,000.
At the same time you have purchased something from this customer on credit for 200.
Instead of paying your customer 200 while they pay you 1000, you can make a contra entry which decrease balance due on your sales invoice by the amount on purchase invoice.
In order to do this, go to Journal entries tab.
Click New Journal Entry button.
Make a journal entry which will credit sales invoice by 200 and debit purchase invoice by the same amount.
Or if there are more invoices involved and instead of specifying individual invoices, you can also contra amounts between customer and supplier accounts directly. This will make MYBOS auto-allocate credit to outstanding invoices on both sides on first-in-first-out basis.
Click Create button to save the journal entry.
Your purchase invoice will be marked as paid in full without actually paying it (which is what's happening in this case).
Your sales invoice will have balance due decreased by 200.