Danish Pilot- With the recent influx of passengers flying with ezy, ground handling crews have had to be increased from 4 to 5 men to turn the a/c in 20 minutes. (GLA routes)
I agree that the 319 with containers may be turned in 15 minutes but not consistently. There's too much can go wrong with this type of loading procedure - equipment failure etc.
The 737-8 is impossible to turn in a short time due to its monter of a hold!
I'd go with the -700 theory.