Many different cabs are designed to work together, Bergs, some Mesa Boogie cabs several Barefaced cabs and others.
The attempt to make "never mix different speaker sizes" a blanket rule is misguided and wrong.
I used a Berg AE112 and AE210 together for several years and it sounded great. The new Berg B Amp has a profiles for CN 12 and 10 mixes, so it seems it was Jim Bergantino's intention that these cabs could be mixed. So yes you can do that.