We wrote a Printer Driver based on UniDrv, and its GPD File is like the one
of the HP LaserJet 5 Series. Now we have a two-page document to
print(simplex, duplex and LongEdge). when using HP LaserJet 5 Driver, the
output job files(pring to file) are the same except that one is simplex
printing command(l0s), the other is duplex and LongEdge( l1s command), the
job data are the same. However, when using our own driver, the result job
file is much more different between the two, including the job data.

Can anybody tell us what's going wrong with our driver?