I complained to support about this issue about 10 seasons ago when I continously played in +1 level competitions from level 4-13 they gave their usual explanation that they need more lower level managers fill up higher level competitions in some servers. The only advantage they could give me was that I earn more competition price from playing in higher level competitions which is utterly ridiculous.
So I resorted to manipulating the draw and I won 6 trebles and a league and cup double in a row. but none felt sweeter than when I managed a league and champions League double playing against +1 level managers.
So now I'm back playing against higher level managers this season and I've kicked their ass! I'm still on course to win my first treble playing in higher level tournaments and frankly I derive more pleasure in winning higher level managers.