Thanks.In my experience this will not lead to the results you desire, I want to encourage you to not do this if possible.
I probably should have chimed in some time ago but anyhow you got some good advise from here and also the person you contacted but this piece of advise seems misguided. Some mild fertilizer that does not include very much nitrogen might be OK, something like 0-10-10 or such but in general fertilizing full grow trees like you are suggesting would be bad for their health.
Not trying to be a downer but the cut to the tree was not good idea and has probably hastened its demise, it is always best to leave nature deal with these things unless you ask an Arborist .
Also it is a true and researched fact that any spray, paint type thing is worst for healing tree wounds then leaving them alone so they can heal on their own.
I agree that painting is bad for the tree. I won’t apply any more.
I spoke to a certified arborist who suggested a fertilizer with nitrogen, who also said not to paint the cut.
Cutting the tree originally was more or less required as it threatened the house.
I understand the tree might not be saved.