That value sets the amount of the increment if you would go ahead and set the memory delays manually, all BIOSes before 5/02 did not have this option and 70 picoseconds was the default ever since 9/13 BIOS. Early BIOSes went by increment of 1, e.g DIMM1 1-1-9-6 DIMM2 1-1-9-5 or 100ps-100ps-900ps-600ps...etc.

This is how it looks on LP x48:


I really would like to see DS, DDS and Skew Model making its way into LP P35 BIOS.