I don't think you were using the term pre-release wrong. To me it's anytime when we wouldn't expect to have the ski release. I don't have an answer for you, but I agree that 13 is high. I'm 5'11", 317 boot sole, and weigh about 190. I'm 58, and I ski all of the time now on a DIN of 7 and haven't had a pre-release in the last 5 years.
|Most of my heel releases happen when hitting frozen avi debris or other crud at high speeds or when my skis get sucked off my feet be some really sticky snow,...
For example, the one above sounds a lot like the following description, a case where the ski meets extra resistance at the same time that there is lots of pressure against the shin.
"....is precipitated by the skier driving his or her shin rapidly forward at the same time as the forebody of the ski flexes sharply. The inadvertent coordination of these movements by a skier who is otherwise erect and in balance can put the lower leg momentarily in tension, thereby allowing the skier to pull the heel piece open with no apparent effort. This classical example of poor technique (bad software) can only be avoided through education--smoother, better coordinated technique. Cranking up the heel piece is not necessarily the solution. Once learned by our testers, this scenario could be repeated, even at release settings on the heel piece well beyond the setting range of any binding now available to the public. "
My real concern is that you are setting yourself up for a knee injury by ratcheting the DIN settings up to a level that they won't release when you get in a situation where they really should. Maybe you can expirement some with the other ski/binding pair, start with lower DIN and see if the same problem exists (or maybe ask someone from Epic that skis the same places you do to watch you)?