You remember correctly although that sort of thing is usually referred to as Alchemy abuse for a good reason: it can make the game trivial and boring unless you set some limits. If you like that sort of thing, however, there's an even easier way that doesn't require any Alchemy training. Take Restoration and as soon you get attacked by the assassin, get to Mournhold and buy a fortify skill spell. Then make a custom spell of fortify alchemy 200 for 2 seconds on self and you're done. You can also pay an enchanter to make a ring with the same spell so you don't even need Restoration.
Aye, I remember reading up on the UESP about it after I'd found I could do this.
Yes, it's alchemy abuse. But for gamers that don't really care about roleplay, or can include such a thing in their roleplay (I did, my char was Arch-Magister of House Telvanni, of course she'd be pretty beastly, but I didn't go too uber. I was still killable, due to weaknesses built into the char), it's a very effective way of playing a Mage.