Ca - I think PA can be multilevel.
Children can use it from where ever they are.
It really helps to focus your teaching. I understand that your helped develop the program for your district. PA is the understanding that spoken words are made up of a series of discrete sounds. Most of the ones I'm familar with I used with 1st's, and seem too basic for my 3rd's, OTOH, I expect some are weak at it, based on writing samples. A little harder on initial, but most of my kids seem to get initial.