It will also depend on WHERE you place the Part Origin(home) IF you put it in the middle of the table you could run out of table. Always LOOK at teh size of what you are about to cut. THEN you will be able to tell WHERE you need to put the 0,0 in order for it to cut on your table IF it fits that is.
I always load the program set the 0,0 and then go take a look at the extents dro's for xmax and Ymax to see IF the cut will fit the table. sometimes you may have to go backl and shift the 0,0 to make it fit.
I would also do a test on your machine command a move of say 100mm and SEE if it moved 100mm exactly.
Just a thought,(;-) TP