If you decide to load your aircraft to APG's weight for a certain RWY/airport, then you better follow it's published procedure regardless of what SID you were cleared on because chances are the APG procedure will allow you to take a lot more weight off that runway.
Like CL300 "MAYDAY" is your password to get ATC's attention.
We set up the APG departure procedure in FMS 3 and if required it is then switched to the PF's side so that he can follow it.
Some places we go into are in mountainous areas, like KESE, KASE, LSZH to name a few. There is no way one could takeoff following the published SIDs and make it to destination on long flights, thus APG.