> Subtler, businesses can try to game their prices to maximize rounding gains; also illegal (jobs: accounting, data analysis).
It's actually illegal there to set prices such that they will generally round in the business's favor? Talk about micromanaging…
If they change the tax rates do you have to update your prices so that they round evenly again?
A fairer policy might be "round random" (e.g. 1.23 rounds to 1.20 40% of the time and to 1.25 60% of the time, since .23 is 60% of the way from .20 to .25). That would be harder to game by manipulating the prices. However, you would need to certify that the rounding was actually random; the result wouldn't be obviously correct for any particular transaction, only in aggregate.
It's actually illegal there to set prices such that they will generally round in the business's favor? Talk about micromanaging…
If they change the tax rates do you have to update your prices so that they round evenly again?
A fairer policy might be "round random" (e.g. 1.23 rounds to 1.20 40% of the time and to 1.25 60% of the time, since .23 is 60% of the way from .20 to .25). That would be harder to game by manipulating the prices. However, you would need to certify that the rounding was actually random; the result wouldn't be obviously correct for any particular transaction, only in aggregate.