Autodesk 2005,07 HP T1100 Aligment issue Speed modes

Hello 
I have a 2 printing problems with the HP Design jet T1100 44-in Printer.  We are
about to purchase this machine but we want to know if anyone else is having the
same problem or is there a fix for it.  We use AutoCAD 2005 here at the office
but we tried 3 prints with AutoCAD 2007 from the same level but different speed
of the machine from place where we will be purchase this unit.    We used Fast,
Med. and best mode.   When we look at our 3 prints from this machine.  We notice
that the fast and med.  Have a white alignment line over our POCHE / shade every
7/8 of an inch. Also every 7/8 a straight or angled like does a “stair
stepping”.  Its like the line moved or the machine is misaligned or something.
  This doesn’t happen on Best mode but at best mode it slower printing time
than our 8 year old HP 750C plus.  So the question is does this machine have to
be realigned by some settings or is it because of AutoCAD 2007.  We have not
tried it out on our AutoCAD 2005 yet.   Also we used the setting in AutoCAD
custom properties and not the setting on the HP T1100.  We tried changing those
setting and the print time was all the same about 7:30m per E size sheet.  Any
info would be great before we make this purchase.  We will be making this
perchance in less than a week.  So we need to know ASAP if this is a normal
problem for this plotter.    On a side note the color prints from a PDF