Both programs use the same plate solving backend. They both write out a raw image that the solver analyses.
Both are pretty sensitive to having the correct telescope focal length and pixel size entered in their respective settings.
One thing to look at when PlateSolve2 is running is to look for the number of extracted stars...too many can be bad as is too few.
What exposure time are you using for plate solving in SGP? Whatever it is, I suggest you try that for APT too
