I am glad that you are observing some improvement of your condition and hope that, as for me, it will grow in the way of healing !
Concerning the ultra-keratinized callosities, I don't think that it is because of an excessive production or a kind of disorder but just the result of a lack of something -that the 'steam' treatment can work out-, just a little detail, which prevents the fresh skin to heal properly.
So, each time the skin peels, does not come off because there are still cells links. Then, an other layer grows, does not manage to do its role because of still this lack of something.
Then, all the flakes pile up together to form these ugly callosities.