After talking with my AD about adjusting our current weight classes here are some things I learned and some that were confirmed.
Many middle school ADs no little to nothing about wrestling (confirmed). The IHSAA has puts out a guide book for middle school sports (learned). Therefore the ADs just follow the guidelines set forth by the IHSAA. Now these are not rules but rather suggestions and ADs not wanting to have to explain to parents why little Billy doesn't have his weight class. They can just say "we use the IHSAA guidelines". These weight classes haven't changed in at least 17 years, probably longer. My AD's suggestion was to contact the IHSAA and have them change their guidelines if we want more support.
Now as far as the weight classes that were suggested go, there are some good points and bad. 22 weight classes are too many but 17 is too few and eliminating middle weights is a terrible idea. I like the idea of spreading out the weights a little bit more instead of 5, 10, or 15 pound increments having it gradually increase to allow more growth and less cutting weight. I took your suggested weight classes and the current ones we use and am trying to enact the following weight classes for our school and hopefully for our county and conference (not holding my breath).
75-80-85-90-95-100-105-110-115-120-125-131-137-144-151-158-168-180-220-280
With a rule about the minimum weight for the 280 class being 220.
And I absolutely want to thank you for attempting to make it uniform and for getting the ball rolling as it as opened up more dialogue on the subject and importance of it.