Hudson,
This may seem a very short answer to a your post, but my 'gut' feeling lies in a response to your last line - "I wonder why the significant difference between the two types of simulator?"
Are both types of simulator from the same manufacturer ?, OR
If from the same manufacturer, did the programme come from the same supplier ?, OR
Did the same group of people within your company carry out the acceptance / compliance with CASA ?
The answer/s may lie in there, different strokes for different folks.
I can identify with your student's response to the 'catastrophic' engine failure. Too often we teach procedures (in this case handling an engine failure with it's performance implications and procedures), with a simple flame-out instead of the 'complete package'. Flame-outs do occur, but many many engine failures follow ever increasing indications of engine degredation. In one 'package' which I created, it began with a loud bump (bird strike), compressor stalls, rising EGT, increasing vibration (lost turbine blades), and finally seizure with accompanying very convincing vibrations/shaking. Some of the astute picked it up early, some needed a little more convincing. The slowest learner turned to me and said "why did all the shaking and vibration stop ?". I informed him that the engine could take it no more, and separated from the aircraft. "Oh, he says, good then, the problems gone". So too, was his base check.
Regards,
Smokey