I'll give a slightly different perspective...many years ago (late 80s), I banked at a S&L that was closed by the RTC. Four years after I closed my account, the RTC called me at work, and said that I had written a check in 1987 for $50, but the S&L had encoded in error for $25 and wanted their money. Thinking they must surely be joking, I asked for a copy. Sure enough, $50 encoded as $25. I contacted my trusty local banker, and inquired on whether or not this was legal. His response was "did you write the check intending to pay $50?" Of course, I said. Then you owe it, he told me.
Charge your customer.
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Providing alternative truths since the invention of time