My form with grid on table with "set skip on" work on VFP9 slower? than on VFP8. The code

local lnStart, lnRecords
m.lnRecord=0
go top
lnStart=seconds()
scan all
thisform.grid1.Refresh()
m.lnRecords=m.lnRecords+1
endscan
wait window "Time elapsed: "+str(seconds()-m.lnStart,10,3)+". Records:"+str(m.lnRecords)

give result:
Time elapsed: 1,375 Records: 59 (VFP8)
Time elapsed: 9,406 Records: 59 (VFP9 shared (files is opened by another users))
Time elapsed: 1,503 Records: 59 (VFP9 single opened file)

Why VFP9 is so slower VFP8??? With sofisticated grid skip to new record take 10-15 seconds on VFP9 and only 0,5 seconds on VFP8...