current method of payment is Must pay first then High (only if their are sufficient funds) then any invoice under the normal priority irrespective of how long an invoice has been waiting to be paid. Rest is making payments based on how much is in the account not how long the invoice has been pending for. So some creditors of large accounts are waiting as long as 3 months to receive payment for their invoice. Is it possible to change the "rules" on the high priority for example so that the must pay goes first, then the old or large accounts as high and everyone else as normal? Normal priority will then only be paid if the high accounts have all been cleared.