"1.5 Invoices. The Developer will invoice the Client for work done weekly. The Client agrees to pay the amount owed within 21 days of receiving the invoice. Payment after that date will incur a late fee of 5% ."
Fee being yearly or monthly? When setting up the variables it was displayed as monthly - but this is not conveyed anywhere in the contract which will default to the Clients best interest (yearly).
A one-time fee incentives them to not pay late, but once they are already late, there is no more incentive since they have already incurred the 5% fee.
You just quote high enough that the "discounted" rate is the real rate and the not "discounted" rate is the penalty rate. Then you're just rephrasing things (discount vs. penalty) to put a better spin on it.
Fee being yearly or monthly? When setting up the variables it was displayed as monthly - but this is not conveyed anywhere in the contract which will default to the Clients best interest (yearly).