QUOTE
Just know this: exp gain does not depend on your level.
With same trainings, perks and stuff, if PF DwD gives me 3.000.000.000 exp, it would give me the same exp even if I was lv 300.
What is the difference? For me, 3b exp are 4% of a level, for a lv 300, several levels.
So, the higher you are, the more you have to grind to have higher proficiency, the harder will be to keep them the same number of levels above yours.
If I understand Tenboro's explanations correctly, level or difficulty shouldn't matter for proficiency gain. The more experience you get, the more proficiency you get.
Let's say a fight gives 10% experience to a low level player's level up, and 1% to a higher level player's level up. The low level player should get 0,4 prof and the high level player should get 0,04 prof, while he also has to fight 10 times as much for a level up (ignoring multiplicators for proficiency above or below level and assimilator training in both cases).
However, if you are not an extremely active player, high level players are still at a disadvantage if they want to increase their proficiency beyond their level, because dawn experience is a higher percentage of their experience "income", and dawn proficiency misses the 4 times multiplicator, meaning:
Proficiencies you use:
Dawn exp: 5% of your level up -> 0,05 increase to all your proficiencies (with whatever level multiplicators are in use)
Gaining 5% of the needed experience to next level up through fighting: 0,2 increase to proficiencies (again with multiplicators related to level)
Proficiencies you don't use:
Dawn exp: 5% of your level up -> 0,05 increase to all your proficiencies (with whatever level multiplicators are in use)
Gaining 5% of the needed experience to next level up through fighting: 0 increase to proficiencies
So, in summary, the higher your level is (or the less you play), the less likely it is that proficiency for the skills you use increases beyond your level. At the same time, the more likely it is that the skills you don't use keep up with your level.