contacted local highly reputable well service company regarding coliform in my well and they told me using too much bleach when shocking well is counter intuitive? They told me to only use two cups 'to sneak up on coliform' and used a burning house analogy about how coliform can sense chlorine

Essentially, I was told if I use too much bleach the coliform hides in the well walls rather than entering the bleached water and secretes a substance that protects them from the chlorine. The guy said its similar to how people wear fire-resistant clothing before running into a house fire. I cannot find anything to back this up anywhere else and if anything it seems to suggest more chlorine the better if you are fighting persistant coliform bacteria. Anyone have any insight? I cannot seem to get my well under control when it previously ran clean for a few years after moving in. Well is drilled and about 67' with 45' of standing water.