There may or may not be fixed price servicing. Certainly, with the wife's 93 I ring various Saab dealers then ring my preferred dealer with last. They always match the cheapest price to keep my business.
And it's really quite amazing the difference between prices for a supposed "standard" full or interim service. So it's always worth ringing round.
Interestingly, I also just had to have a new air con condenser fitted on her car as a tone had gone through it. My preferred Saab dealer were as cheap as any of the specialist independents I rang!!! But then again, they at least seem to know what they're doing with Saabs as opposed to the majority of VW dealers I've dealt with over the years who don't have a clue!!!!