If you have chloramine, instead of chloramine, the large changes in water are adding significant amounts of ammonia. Chloramine is chlorine with ammonia, and the chlorine is neutralized and the ammonia is bound. The bound ammonia is available to the filters for conversion to the nitrite and then nitrate, but there may be so much with the water changes that it has not been converted yet. Check the tap water for ammonia and it will tell you if you have chloramine. I would suggest use of an Ammonia Alert Card available from the local pet stores, as it will show whether the ammonia is bound and safe or unbound and toxic. If toxic, add some Prime, Safe, Chloram-X or whatever chloramine treatment.
The fish will often continue to flash some following the Proform C treatment, but I have not seen the clamping continue, so I would treat with Prazi. Add it with one more dose of Proform C at 1.5 times normal dose. With the low temperatures, some of the parasites may have not been in a killable life cycle, but with a time delay, they could be now.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard