Okay, to make this one clear, I'll have to tell you what I mean, simply...
In the Black and White versions, after defeating N and Ghetsis, you go to the East side of Unova (ex. Route 14) and the trainer's Pokemon are in their mid 60's (lvl.-wise).
AND
In the Black 2 and White 2 versions after defeating Iris, trainer Pokemon are in their mid 50's (lvl.-wise).
How is this level difference possible?! Is it because how high N and Ghetsis's Pokemon are (lvl.-wise) in Black and White? Does this count for after you beaten the champion too in Black 2 and White 2 too? I am clueless...