[youngfg]

What are the units in programable I/O

TPS isn't percent, it looks like 0-1024 for the 0-5V input
VSS looks like it's MPH *1.6

How are the various units actually calculated?

[dazq]

Yes aux io is 0-1024 , there is no scaling or formatting.
Specific inputs are scaled and formatted as appropriate and so differ .
The data in the serial3 stream is formatted and scaled as shown in the list on the wiki