It looks like 3Shape maybe? Which I am not familiar with (I do think they have some interesting terminology though).
I would say that using the 3+1(4) axis setting will prepare the machine for 3+1 milling (block-out undercuts).
I am not familiar with the “cad block rotation” settings. Might be the maximum insertion direction that can be set.
So depending on which machine you have, that can be set to a max of 35 for the 5x400 and 5XS (although we do not recommend pushing to the extremes).
Drill compensation: For zirconia, the drill radius should be set to 0.6mm. For PMMA and Wax it is typically set to 0.4mm.
Not sure this helps...