Ng Value in Cessna 208B Grand Caravan

Hello, all:
I was looking for a simvar which represented the Ng in the C208B; I found where someone in Air Manager used the variable A:GENERAL ENG PCT MAX RPM:1 for this and it does seem to follow the Ng displayed on the MFD in the aircraft but it is quite a bit lower. For example, at idle, the Aircraft is displaying an Ng of 72% while this variable only shows 59.8%.
As this is quite a bit off, I wondered if this variable actually represents the Ng, or perhaps requires some kind of modification (because the simvar never actually says Ng), or finally does it represent something else entirely that follows Ng in some way?
I would appreciate your thoughts on this topic. Thank you in advance for any assistance you may give.

You might want to edit your tag for this post & add “SDK” - folks watching that tag would have a good understanding of simvars too.