Commitment limit calculation

Hello

Could you pelase tell me where to find the explanation of commitment limit calculation

I have one customer

account balance is 2078;74

DELIVERIES 0

Orders 0

Credit limit is 2500

COMMITMENT LIMIT IS 2500

when you create a sales order the commitment limit is reached 807.59 and the popup is launched but I could not figure out how this amount is calculated

Can soemone help thanks