The problem with sending out voltages 'custom' packets can make the transponder not work with Mylaps decoder, not the opposite, so it's not a decoder default to be set. This of course for the published numbers that come from Howard original code. If you go with your own numbers and don't mind for Mylaps compatibility, the protocol can be expanded without problems.
One main issue is that Cano protocol from decoder to PC does not allow to send voltage information to the scoring software (or temperature or hits).