The clown loaches were flashing after the salt was added but they are usually in hidding alot and I've heard alot of noises coming from their hidding area which leads me to believe they were flashing all along. The yoyos have been seen flashing the whole timethe way you posted made it seem like the loaches were flashing after the first round of treatment.
I would probably stop the current med...that just makes me nervous with the amount of sensitive fish you have in the tank. Paraguard I have used successfully in tanks with all the above mentioned fish with great results and from what I could tell no ill effect to the fish.