I live near KSEA whose declination is about 15.61° E. I fly FSX-SE and have applied Hervé Sors latest magnetic declination corrections. I get a variety of course directions using flight plan tools. For instance, I built a flight plan from KSEA to KBOI via V4 using PFPX. The first leg of the flight plan from SEA to YKM shows a course of 108-110° magnetic. The Seattle Sectional Chart shows V4 as constant 104°. FSTramp shows a course of 105°. The sectional chart is correct, so how do we explain the variation between the Sectional and PFPX's course of 108°?
Does anyone know if it's possible to update PFPX to use the correct magnetic declination variables?
Thanks in advance for your help.