From my previous post:
With that, "the level of the staff member does not impact the effectiveness of the specialty" since specialty is computed first with a random thing.
For illustriation purposes only and computations are not precise:
Let's say you have a 33-old player with rebounding at level 10(let's just talk with one skill).
Two scenarios:
1. With your career extension trainer: there's a chance that he will not have a drop and retain his skills level but if you're not lucky enough your player will drop from 10.0 to 9.0.
Afterwards, training module will compute for training factor which includes: age, skills, trainer level, etc.., With that computation he can have 9.1 instead of just 9.0. The effect of the trainer level is to minimize the drop. The higher the trainer level, the higher the training factor is.
2. With no career extension trainer: surely your old player will have a skills drop unless the random thing gives you a lucky week.