If the numbers are actually 110 to 100, there is a more complex reason to it than just the age gap tbeory. Of that I am certain.
Here is what your insistence that it is the age gap leads to:
– Tacit approval of every personal criteria invented by shadchanim and/or parents. Theres nothing wrong wih saying we can’t go out with baalei tshuva, or someone who graduated high school with only a B average, or someone from a broken home, or someone whose distant relative is rumored to have been sick at some point, or someone who davens in a shul I once felt uncomfortable going to, or someone who lives on Kings Highway, etc etc. Nothing is wrong with this, because the main thing that is wrong with shidduchim is just the age of the boy and girl.
– A new criteria is introduced to the list of moronic ones already in effect. If the relative ages are not good then nix it. Girls have to wait longer than they’d like to start dating; boys have to go out younger than they possibly should be and with girls who make them seem inadequate.
If all the age theory did was make it “kosher” for a girl to be older than 22 and to make it kosher for a girl to be older than her husband, then kol hakavod. Removing artificial restrictions is a good thing. But it leads to a worsening in the restrictiveness, and the bad clearly outweighs any good. Especially because the whole theory is based in simple mindedness and ignorance of external factors.