Maybe GST has something to do with it?
I did one of the 12 month wonder courses but the problem was it took 16 months not 12. I put this down to what glenb said. Shocking weather in Vicroria in the winter and a lack of instructors (and indifference) at my school.
Getting to the point though. I do believe that if you are enrolled in a 150 hour course and you don't look like you are close to completing your CPL in 15 months you should be changed to the 200 hour syllabus. The 150 hour course is tax exempt because you are considered to be a "full time student". Taking 2-3 years to do a 150 hour CPL course doesn't make you a "full time student", hence you shouldn't be entitled to the tax break.