Question to real world pilots

Hi!I have observed the following in PIC:If I have a self-made waypoint in my flightplan, such as 3640N239/220, then I can insert this information into the FIX page. Now lets say I change my flightplan a little bit, and remove this slef-made waypoint.If I want to see when I will be abeam this self-made waypoint, I can press the Abeam LSK on the FIX page. So far, so good. The problem arises, when the FIX pages calculates the abeam point, and I select that line to insert the new waypoint into my active RTE. The FIX page calculates the following waypoint: 36401150/1.5 (36401 being the self made waypoint I created before). This new waypoint will not be accepted by FMS. Quite understandable, as it contains place/bearing/distance information from a PBD waypoint. My question is as follows: what would the real FMS do? Calculate the exact latitude/longitude of this waypoint?Thanks,MarkEdit:I just tried the same thing with PS1.3, and found the following: As long as the PBD waypoint is not on the active route, it can not be entered on the fix page. And if it is, then pressing the abeam LSK (after changing the flightplan so that the aircraft will not overfly the waypoint) it will create a PBD from the PBD (just like PIC), which can also not be entered on the legs page.