More to the point: The arcane archer is a one-trick pony. The magical arrows are a really, really useful ability; no one else at these levels is going to be as good at overcoming DR as the arcane archer. It's the main reason why I advocate this class when doing epic archer builds; sub-epic, it's the worst archer PrC out there, losing out to a straight cleric archer by a good measure and being utterly blown away by the deepwood sniper, peerless archer, or OotBI.
Let's clarify here: This arcane archer is at best 20th level. That means +10 arrows. OK, this is pretty useful; +10 bonus damage to an arrow, with up to four arrows per round fired. Woo hoo. You, as a sorcerer, will be unleashing at least one 9th-level and two 6th-level spells in the same round with Auto-Quicken. That means that you get two Quickened disintegrate spells (save vs. an insanely high DC or die, successful save still means 5d6 damage) plus a wail of the banshee, power word kill, gate (60 HD nets you two solars if you want 'em) or any other uber-cheese spell. And you're worried about 40 extra points of damage per round?
Honestly, the arcane archer player is probably going to feel like a complete second-stringer compared to you, Cloudgatherer. He'll most likely end up mopping up foes with magic immunity or those who pass their SR checks. You'll be doing the main mauling.
Incidentally, you really should take AQS x3 right off the bat, since you're building your sorc from the ground up. Skip one of your Automatic Still and Silent feats; they're sorta useful, but not nearly so much as Quicken. Having the luxury of unleashing three 9th-level spells per round is pretty insane.