FFA350 vs JD320 flight plans

[Maki67 0]

Hi hope someone can answer this:owned JD320 and FFA350 for sometimes now but bumped into some odds-with a320 can obtain full plan by simply  entering departing and arriving sids and stars with fully listed sids and stars in the flight plan and this appears to be done automatically without need to enter all sids and stars enroute. Hower in a350 can still get the correct plan by entering departing and arriving sids and stars but plan does not show any sids and stars in between TC and TD unless of course i enter all sids and stars manually. Still can fly nicely but don't understand difference in concept or is it just the way how JD and  FF decided to program their aircraft and can someone explain is it like that in a real a320 and a350? Many thanks un advance☺