As pointed above, the tolerances are much narrower in a CPL course regarding heading, time and altitude. You are also expected to deal with partial panel situations and cruise climbs/ descents for pax comfort. There is a lot more memory item drills to do with engine failure/ fires compared to the PPL which with the greatest of respect is much more simplified.
The CPL course is very different however you seem to have done your training a very different way from the norm with your SEP IR and MEP IR done before your CPL and ATPL exams. This would have indeed giving you the idea of an overlap as you would have already done it before where as others who did it in the way flight schools offer, see it as building on the last bit of training one did.
One thing you will have to consider is general light aircraft GA flying is done on a more amateur level which was thought during the PPL with the primary understanding of flying safely. during the CPL training, yes safety is a priority however you are also trained to conduct flights in an expeditious manner. A simple example of this is you fly approach speeds in commercial flying and never stall the aircraft on the flair. In the PPL you are trained to hold the nose off the ground and "not let her land" to make sure you do not have a nose wheel landing and to land on the main gear first.
In general the CPL training gets you to a more refined standard of flying compared to a PPL where you are pushed to perform accurately as well as safely throughout. To make sure you meet the standard with a good chance of passing the test, the CAA have decided that a minimum of 15 hours is required in order to get a student up to the required standard and be comfortable as well as competent.
Last edited by Jet Simulation; 29th July 2013 at 16:19.