Low lvl diffrence - cant go rdf

Hi. I dont understand this policy.
In specifc dungeons i have “29-38”, “30-40”, “30-40” thats all. I am lvl 33 my friend 30, and we dont “meet requirments” he must have higher lvl. Like we are in this 3 (x-y) range and only 3 lvls diff! Why we cant queque together?