[philiphodgen]

That's the wrong question.

You have contracting engineers. They get nervous if you pay slow.

Presumably they are good people. You want to keep them. You want to attract more, better engineers.

Pay them in 2 hours.

Imagine what happens then.

Happiness.

Ability to recruit.

Improvement to your cash flow. You don't have to pay more if you remove collection risk from your engineers' brains. And they have instant cash.

Pay instantly and frequently.