Scan tool readings

[pjaf]

I have a LS2 powered Solstice with a 6L80 behind it. Car runs great. However when looking over the engine data with a couple of different scan tools the one parameter that states % power reads backward. Idling it will read 100%. When driving it will decrease in proportion as I add throttle. Does anyone know how the scan tool calculates this parameter?. Does this data affect my tune? Or the Transmission shift? TIA

 

[arse_sidewards]

It's probably just reading TPS or MAP

 

[pjaf]

It's probably just reading TPS or MAP

I don't believe that as I have compared the data from both of them against what I see on a stock LS and the data is pretty much the same. I don't understand how the tool gets this info. Is it a data point from the ecm? Or is it a calculated value that the scan tool comes up with?