Myka, I'm really glad that you have things "stable". The seasonal part makes sense.
I understand what your vet is saying about the allergy testing. I know when I tested my new girl, all the environmental stuff lit up, so there is nothing specific to tackle, but all of it. However, it has helped me with the grasses - she loves to roll in the grass, and I know which ones she is most allergic to and I can diminish that. It's also good for me to know that she is not allergic to her bedding, my last dog was allergic to cotton of all things
I also find the food portion helpful, but everything still has to be challenged, so I can see that either way.
Anyway, it sounds like w/o the allergy tests you have things managed, which is a huge relief, congratulations