People say q-pon rather than coo-pon??

Never ever heard that one, MG.

The coo- sound in "coupon" (= Fr "cut thing" more or less) comes straight from the French, as in "couteau" (coo-TOE) = knife.

I could see "cou-" being anglicized as "cow-" (like in count, out, amount etc), but not as "cue-".

Then again, stranger things happen. Especially over the Other Side.