Two things to note;
1) the turnaround system does not take into account the stage length yet here. We can turn A320 series in domestic airports (no refuelling/minimal cleaning) regularily at about 30-35 minutes but intl turnarounds with full service take longer and they have usually 55-65 minutes in between them. This is something that is planned for future in AWS.
2) second thing to note is that you should have also a good turnaround time at home base, this is something that people usually miss.
In real life, we can, and have, turned a 319 in 21 minutes, or a 717 in 16 minutes, but it depends on many factors all coming together.
Can the gate get all of the pax on and off, and do the security check quickly? (Full load at a Holiday, forget it.)
How big is the download, and do we have to sort on the ramp for connections?
Are the fuelers on-time?
Are we throwing bags, or stacking them?
Can the crew do without a starbucks run for this turn? Etc,etc,adn....
Will the crew be done with the checklist soon enough to beat the guy across the alley out?
Does the stew want a full cater?
Do the lavs need dumped?
How many 400lb. wheelchairs are we going to be wrestling?
Is the ramp/gate contract, or company?
(NOTE: A Company ramp is ALWAYS more motivated than a contract ramp!)
Hell, I even once turned a 767 (charter) with 400 bags off/400 on in 31 minutes, with a crew of 4 ramp and two gate, but I sure wouldn't want to try that every flight, every day. Sometimes, you just get lucky, and everything comes together. No kids wizzed on the seat bottoms, the sky is blue, and the load is only 10%. Most of the time, it doesn't, yet somehow, we still manage to get'em out on time.
I can double, or even triple up crews to do a quick turn, if I need to, but the minimum time is there for a REASON. And let's not even talk about working with a union ramp!