Potential issue with needing more than one precision value

I don't fully understand this, but perhaps others might be able to decide whether this is an issue or not which needs to be addressed.

Raised by lassi.liflander [here](https://forums.buildingsmart.org/t/precision-value-and-two-checks/1096) and [here](https://forums.buildingsmart.org/t/is-one-precision-value-enough/1075)

Ping @berlotti @aothms @TLiebich