Consider another approach.
Depending on how good you need the other side to be in register, and how good the hole is (reamed is preferable), I have sometimes used a carbide rod held in an ER20 collet as a locating pin. Put the collet in the spindle; push the part onto the rod; and then reload the part into the vise without moving the table/fixed vise jaw. The fixed jaw gives you an X reference, and the rod centers the part under the spindle. This isn't perfect, and it depends on machining the reamed through hole from side one as well as having a decent side to index against the fixed jaw. IF the stars align, and the part and fixturing are amenable, one can get a thou or a bit more register and repeatability. Not high precision, but sometimes good enough.
Another option is to gang parts to make multiple copies in one setup, so when you flip the work you're indexing one hole but that single hole provides register for 4 or 8 individual parts. Takes just as long to do the single hole, but now that job is averaged over multiple parts, so it's faster per individual part. Again, not necessarily usable with parts that have much side geometry.
Third option is to write your own probing code. That was easy in Mach3, don't know how simple it may be in PP.