I personally have not ever tied my own loop on, but looking at your link, it is the same knot that all of the shops have used on my existing loops.
That being said, I have never had one fail.

The mushroom on the end of the string does not actually hold that much weight. It simply prevents the end from pulling through the knot (and also fraying). When you pull your bow back, this slight tension on the mushroom causes the rest of the knot to tighten around the string (and itself) and secure it. The knot is actually held by the friction of the coils in the string aganst each other and the bow string.

I would bet that if you tied a loop on, and left the ends a little long and unmelted you could shoot the loop securely. The fraying would drive you crazy (tickle the side of your mouth) but it would hold secure.

You say that you have about 30 shots through your rig with the loop. At this point the loop is probably about as tight as it will get, and should be secure.