If you have a cup with "mm" stamped on the cup (after the 22) it is possible that it was made a couple of years ago when we (PHC) were referring to the cup depth. We stopped doing this for several reasons but a lot of us still use the older cups. They are exactly the same as the more recent PHC cups with a bigger "22" stamp and no "mm".
You should get some answers from horn players who do use the 22 & 22A cups.
