If 99% of your customers do things the wrong way and 1% wants to do it the "correct" way that you don't support, there's an easy business call: you do it the wa

If 99% of your customers do things the wrong way and 1% wants to do it the "correct" way that you don't support, there's an easy business call: you do it the way the 99% want and tell the 1% "Sorry, we don't support that. Hopefully you'll find a provider who does." Massive portions of the economy are built upon that principle, from IE6 to UNIX to C to VHS to QWERTY to 120V electricity to U.S. custom measurements to MM/DD/YYYY date formats to the use of decimal (as opposed to binary) subdivisions in the first place. Context matters too: both of these examples are financial modeling as opposed to transactions, where (as riskneutral's sibling comment points out) floating point error is swamped by the errors in your models in the first place, and some concepts can't be modeled at all with integers. Also regulators explicitly don't care about this area: if your models give incorrect results and you trade on them that's your problem.