I can't really help you with the NBAA pay rates...but a position in Jax will likely pay less than an equivalent position in PBI. Jax is a fairly low cost area of Florida, so the salaries tend to reflect that...plus, there aren't that many flying jobs up there, so that drives the salaries down if there is a high pilot to job ratio.
I'm just saying this based purely on my experience in Florida(I live here and used to do a lot of contract here)...I would expect a PIC in an 800XP to make about 70k-80k, SIC about 45k. Tack on another 10-15k in areas like PBI, MIA, FLL, etc.. I was offered a job flying an 800XP out of TPA for 75k, but it was an on call 24/7 gig with a lot of middle of the night callouts, no hard time off, and lots of time away from home. No thanks.