So the answer to the OP's original question is....
You can pretty much do whatever suits you.
If you are an owner or operator seeking to maximise returns for hire, use a system that tends to over read.
If you are an operator seeking to minimise costs, use a system that tends to under read.
Using a combination of both? Pure genius
If you are a line pilot seeking to comply with regs but stay employed, well, that can be awkward.