You have identified the difference in your question. When G84 is used on later Mk's of machine there is an additional column, this is marked H and as you say provides multiple passes to the cycle. The depth of cut required is entered into the H column and the control panel computes the final cut if the total depth of cut in X is not exactly divisable by the dimension in H.
If entered in MFI you will see in the Comments column the number of passes per cycle.
On the Mk2 machine G84 is 1 longitudal cycle so the dimension in the X column is the depth of cut for the cycle. This does save entering 3 additional lines of code to achieve the same movement of the tool.
On both machines after using G84 the tool finishes at the start of cycle position.