Ah, right.
I was just reading off the chart but they are capped at your level -2. Still, all that does is lower the number of allies they can use the Community blessing on by 2, for a total CL hit of -8.
CL 674 is still pretty good, IMO.
Another interesting thing that I'm surprised I hadn't heard of yet:
Construct Armor Modification.
It's expensive as hell, but basically you can modify a medium construct so it can be worn like a breastplate. The kicker? While wearing your construct, any attacks made against you have to target the construct first--meaning that they literally have to go through the construct to get to you, and all it's hp, immunities, and defenses.
Of course, as written construct armor can only be created and worn by the person who made the construct in the first place, which could be a bit of a problem since casters generally don't favor the "put on some medium armor and wade into battle" approach.
Still, between that and Construct Limb Modification, which lets you wear a small construct on your arm to get their melee and special attacks, a caster with Craft Construct and money to burn can effectively play Iron Man now. Granted, since you can't wear construct limbs over your legs it'll be "drunk-forgot-my-pants" Iron Man, but really, isn't that the best kind?