Accounts Payable Discounts

Trying to get a sense of what most companies do when it comes to payment discounts. Do companies have discount allocation policy set to 1) Allocate, 2) Prorate, or 3) Expense Discounts? I'm trying to understand how we can do the configuration so that the discount, upon payment processing/posting, is applied at each voucher line systematically...and in the process, uses the same GL account, dept, other Chartfields that are recorded at each merchandise voucher line. I understand that this can be achieved by 'Pro-rate' discount configuration option....and that no Chartfield inheritance is involved in this configuration. Would appreciate responses as to what your company does.