Yes, it's completely normal for the heat treatment.
What the heat does is accelerate the lifecycle of the ich bug. This will cause any fish that have it already to most likely show signs of worsening, but as the lifecyle proceeds at an accelerated pace it will pass. The next phase of the lifecycle is the "free swimming" phase, wherein this is where the other inhabitants in your tank are susceptible to it. However, the ich can't survive in the temperatures above 85, so this is the effective way to kill it.
The reason the meds you've all used in the past are uneffective are because Ich is only susceptible to meds when it's in its free swimming phase, floating around the water column. This is the only way for the meds to gain access directly to the bug. People that have had success with Ich meds are typically because they dosed at just the right time, whether they realized it or not.
Make sure to maintain your temperatures for 2 weeks AFTER you can't find any more white spots. This ensures all of it has gone free swimming and get killed by the higher temperatures.