WPRTDATA-DRAW-UNITS question

I was wondering if anyone has had much luck using the WPRTUNITS-INCHES-ABS draw units.  I am currently working on a project that requires some printing on a pre-printed form.  I was originally using the WPRTUNITS-CELLS draw units, however, after printing on multiple printers I notices that my text was moving up or down on the page depending on the printer.  After reading documentation, the INCHES-ABS feature looked to be more consistent.  When I started trying to use the INCHES-ABS I noticed that I was not able to print within about half inch of the left margin.  When I tried this I get the error that I am not within the printable area.  I am trying to figure out if I am doing something incorrect or if this is just how it works.  When I use the CELLS option I am able to get within a 1/4 inch of the edge of the paper.  I have also tried the other "CELLS-ABS" and "CENTIMETERS-ABS" and have had the same result where once I get to within about a 1/2 inch of the edge of the paper it gets the error code "-7" after the call to "win$printer".

Thanks, 

Scott