i assume you're putting the thrush treatment in those large cracks/holes in the middle of the frog between the heel bulbs as well, right? That is also thrush there that most people tend to miss. ;)
Yep, I squeeze it in at the top of the crack (heel bulb?) hold the foot up to see how far it spread, then squirt some more into the crack/hole in the frog. Then ijust hold his foot up a while to let is seep in there.