LANDesk support informed me that the following applies.
PXE Boot menu differences:
PXE Menu = mtftp transfer
Privisioning = tftp transfer
The issue for me is that the mtftp does not work for the Lenovos. The tftp appears to function without an issue. I have modified the boot.wim file on my reps to load PXE Menu either way so I have a work around for the time being. It does indeed sound like it's an issue with the BIOS on the units and their incompatibility with the mtftp transfer of the files.
This link has some addtional information as well.