just to add to Temr suggestions:
- make sure your pressures at the same datums. Field/region pressure will be at datum from Equil while BHP (i think) at top perf unless you specify it (either COMPDAT or Welspecs)
-depending on your field size, column and permeability your BHP9-5 etc may be different from FPR
- some software packages for example S3Graf allow input of pressure and time with text file so you can compare pressure from well tests etc to FPR from simulator
good luck
ps. sorry don't have manuals with me and cannot say re- BHP datum