fiber termination tools

We've always done our own fiber termination in-house using Corning Unicam (currently Unicam Pretium) tool kits and ends. Over the years I've dealt with fiber (primarily 62.5um mm FDDI), I've noticed that fiber seems to come in two "styles". Some lets me strip the buffer and coating easily in separate steps using the buffer/coating dual-notch mechanical stripper from our Corning tool kit. Some, it seems the buffer and coating are fused and the coating comes off with the buffer, but because both are being stripped at the same time, much more pulling force is needed, and the buffer/coating has to be removed in small steps or the fiber breaks :frowning:

First, I wonder if anyone knows why this is? Second, I wonder if a thermal stripper would help and is preferable to a strictly mechanical stripper?