I don’t think anyone means to put ALL calculations through a reduced representation. That’s a terrible idea. But if you are discounting cash flows or something,

I don’t think anyone means to put ALL calculations through a reduced representation. That’s a terrible idea. But if you are discounting cash flows or something, it won’t make that much of a difference if you leave the discounted version in full float / double representation and then add them or reduce them to 2 decimals before adding* High finance uses float / double in general and doesn’t bother with the nuances of decimal representation or IEEE 754 unless they’re working too close to the silicon rather than doing model work in higher abstractions. * software that allows only 2 decimal representation must account for these discrepancies by default even if it’s only off by a few cents