I did some flying out of Parafield and was quite interested to note the different circuit techniques of the different users. The grobs and tobagos seemed to fly appropriately sized circuits and most of the other circuit users seemed to feel the urge to use the entirety of the (at the time) GAAP zone...
When I was flying out of Parafield, the Tobagos were not a problem. The Grobs on the other hand flew massive circuits. At the time I was given the impression that it was the type of a/c, low ROC etc.
Maybe it was the (then) Grob instructors trying to log extra hours? and now its the instructors flying the other assorted a/c increasing their TT?