Raystar 130 retro kit to C80

[drbridge]

I installed the new RS130 using the power backfed from the existing terminal strip and omitting the power supply cable to SeaTalkng as described.
The new gps works great. I installed it in the cabin just below the fiberglass roof and it seems to pick up satellites very well in sea trials.
One curiosity I came across on my system is while checking for power feeds in to my terminal strip I found that with the c80 powered up there was
10.45 volts being supplied from the c80 to the terminal strip. With the auto pilot powered up there was 12.1 volts being supplied to the same terminal strip. The RS130 seems to perform well with either or both of these power sources turned on.
My question is, should there be 2 separate power sources coming in to this terminal strip? And also, why would there only be 10.4V coming from the c80 and is the lower voltage good for the gps to operate on?
As I said, the system seems to work fine like this. I just want to make sure I keep the system healthy.

Thanks

Doug