I had a GM tell me that I couldn't use store an intensified Shocking Grasp inside a Spell Storing Weapon (Playing a magus, have the spell and the feat). I disagree, but will only be able to prove my point with something official.
There are a ton of posts on spell storing and meta-magic, although most seem to be on the use of meta-magic rods. I'm NOT asking about the use of meta-magic rods.
I'm hoping someone has a saved location for a post from a developer or an official errata.
What you have is a people problem not a rule problem.
GMs (hopefully) are going to be right more often than the players, but all the time is an impossible thing (as the rules are intentionally vague at times). Telling US about it isn't going to do you any good as it's the other guys issue and he's not here.
Hopefully you've tried to talk to him.
Suggest your GM talk to other GMs and figure this issue out. This is a simple topic and not complicated.
Otherwise consider it some foible in his world and continue on or find another game. Just remember it is just a game and not reality or even close to reality. Nobody is gonna give you $1 if you're right.