As previously mentioned time and time again, Arcane Arrester reduces the spells base Force-based effects -- you know, the things the spells actually do to the character -- in half. That overcast Force 12 Stunbolt is only going to do 6S damage at its base, not 12S. If you can't wrap your head around why that's a fantastic benefit all by itself, that's your malfunction, not the rules. Arcane Arrester does not affect the success of a spell. It reduces the effectiveness of it when it does hit. Counterspelling, Spell Resistance, and Astral Hazing are completely different mechanics from Arcane Arrester, and their primary function is to reduce the success of spellcasting. Not Arcane Arrester. Completely. Different. Mechanic. Just as the damn quality states.
I'm done repeating myself. If you're too obtuse to catch on that your "interpretation" of the rules is a house rule, fine. Live in self-inflicted ignorance. But that's exactly what it is: Blatant, unquestionable ignorance. I have no idea why you can't admit that to yourself, but c'est la vie.