Keyflow Sensi-care, Anyone Use?

Anyone use Keyflow Sensi-care? Pros and Cons. Likes and Dislikes?
Feeding a picky, allergy prone PPID and IR 27 year old welsh pony with a few missing teeth from EOTHR and founder HX. I received a sample of the Sensi-care and he seems to love it. I was hoping it was a complete feed but according to the label his serving would be about 2lbs a day which still leaves me with doling out chopped hay, timothy pellets, and regular hay.
He currently eats 2lbs tim pellets, 3lbs Chopped hay and the rest is made up in fine 2nd cut for 10lbs total (he weighs about 490). Vit E and a multivit.
Would it be worth replacing some of his hay with the Sensi-care? I really don’t need to change his routine but I’d very much like to have the option of something else to feed him if he has one of his picky spells (which he’s had for years and appear to be “just him being himself”)
I will add most commercial feeds with additives give him hives so that is a concern and why he’s not on a complete feed.
Thanks.