53.37% and 61.29%.
Given how this houserule won't function outside extremely-limited campaigns, I don't think it's quite useful for others. Still, if you want unrealistic gunfights because the alternative is very-long gunfights, it's an understandable houserule.
However, do keep in mind that the target isn't just standing there, he's actively avoiding the attack. Sure, you only have ~53% chance to hit on each shot, but that's because he's trying to avoid being hit, and that's against a single attack. If two people fire at the same opponent, there's only 2/11 chance they evade both attacks, due to the defense dice dropping. And the odds we're talking about here, are the same ones you'll get with good cover with your houserule. So the PCs firing at a group of gangers in a warehouse shootout would result under your rule in people easily dropping, while without it you'd take ~3 shots per enemy to hit them, and ~2 hits per enemy to take them down. With 2 IPs per CT, that's still a gunfight that's over in only 9 seconds, much shorter than a shootout in the average tv-show or movie takes, and less rounds fired. And your PCs are at that level, they're not expert shooters, they just know how to use a gun. So of course they're not going to hit bulls-eye when firing at an enemy that's actively trying not to get shot. If the guy was simply standing there, he'd have 0 defense dice after all.
(To illustrate: A gunman fired more than 65 rounds in a shootout with the cops, he killed two people, both of which pretty much by surprise. In the actual shootout, he wounded 4 people. In another shootout, the heavily-armored bankrobbers fired 1100 rounds, one got shot over 20 times in the legs by automatic gunfire by SWAT, before then the cops didn't manage to properly damage them, aside from a few lucky hits to the arms. So that's half an hour of lotsa cops firing and not hitting, and 1100 rounds only causing 18 wounded, with assault rifles and pistols.)
So while I understand you want to keep your gunfights short, I should note it's rather unrealistic, and due to the restrictions, won't really work for near-any other table.
By the way, defense isn't agility+intuition, so I assume you typo'd there.