Not exactly sure of what you are referring to. There are many ways to institute a "Cap." I was not at DAL back when they had a cap but I will take a crack at how I understood it worked. Hopefully one of our elder statesman types can chime in and correct anything below that is incorrect and add to it.

You could credit more than 75 hours but you were only paid for 75 hours.
Any credit above 75 went into a bank system (Bowwave) that would apply to the next/future months.

Not sure how premium flying was paid under this system.

Scoop