"_*Permanent liability*_"
Are you insane?
You have the cash in-hand. The customer has made an interest-free loan to you.
You're ACTIVELY trying to *DISCOURAGE* positive cashflow!?!?!?!?!?!
You should execute the exact opposite pricing scheme: provide discounts to your most loyal customers who are willing to provide you cashflow long in advance of your incurring an expense to provide services to them in order finance your operation.