Yes. I searched the forums for almost two hours and found it:
(203810.34)
The user csanyes was also known as Raymund (he was even BB-Raymund for some time as far as I know) at the time of the post. Later a former GM and MOD (Crazy-Eye) links this post in another thread: (212072.6)
There is the difference between the spec (all levels have the same on) and than the influence of the skill during the training update.
Its weird that he says "the level of the staff member does not impact the effectiveness of the specialty" but then appears to contradict that by saying trainers with higher levels reduce the value of the drops.
I think what he actually means is that if you were actually training an old player only then would the trainer level reduce the drop and that would be because of the small amount of training gain the player receives.