Please consider, if I request a copy of a check to prove a payment to the IRS (or anyone else) the last thing I want you to give me is a substitute check. It's a live encoded item which, even though I only sent it to them as proof, the scurrilous toads could re-deposit. Whether they did it in ignorance or with intent, you would pay it a second time.
Banks will continue to provide customers with garden variety copies when all the customer wants is proof of payment. Customers will get substitute checks only when that is what they absolutely need under the circumstances.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.