Still hadn't figured out max range of apex services yet – I know I tried one at 140ly and was out of range, and had one reported at 100ly successful.
Today, I wanted to go see an engineer at 100ly away (Sol to Domino Green, in Orishis) – right at 100ly, so I figured what the hell and booked an apex. Trip out went fine.
Did what I wanted at Domino's place, then hit the apex board to book the return trip to Sol – only to find that, while Sol to Orishis was in range, evidently Orishis to Sol is NOT in range, and I couldn't book the trip…
I'm not stranded – I figure I'll be able to do the trip in stages, finding a destination to book part way there, then booking the rest – it'll be frustrating, but not critical – but it's a little frustrating as there's also not a way I'm aware of to call my ship here…
Anyway, just be aware if you're booking apex a long way – they may not be willing to bring you back in one hop….
edited to add: yeah, found a system along the way to book to, enroute now. Should be able to book the rest of the trip from there (or call my ship, as I picked a larger startport for a destination this time).