There is no legal course requirement for the 200 hour CPL, as long as you meet the minimum hours and pass the flight test you should be granted a CPL.
The 150 hour course allows you to gain a CPL in reduced hours by completing your flying and theory in accordance with a CASA approved school syllabus (the AOC will list training approvals). Theoretically you have condensed the flying into structured lessons and it should result in the same or better standard than someone who just flies the 200 hours without guidance.
You could save some cash by including the NVFR as part of the CPL hours.
Ratings and endorsements can all count towards the hours for the 200 hour CPL. With a 150 hour course the school may have an approved syllabus which includes NVFR or aeros etc...
This is the day VFR syllabus extract regarding the assessment flight;
2.9.2. Prior to undertaking a CPLA flight test, a 200-hour candidate must undertake an assessment flight with a Grade One flight instructor. As a result, the instructor is to recommend as appropriate, that the candidate either is ready to undertake the CPLA flight test, or should undertake, in accordance with the relevant parts of the Day VFR Syllabus, a tailored course of training designed to prepare the candidate for the flight test.