Mis-understood ARp head bolt instructions...

If you do loosen them all the way, you'll need new head gaaskets. I would leave it where it is.

Leave them like this.

I think it's absolutely safe to back them down (not fully lose) to about 50 ft-lbs, then pull them back up to 60 if you're worried thay you overtorqued.

But I'll tell you, most folks either ignore or don't like/trust that ARP aluminum head torque figure, and they torque them on up to 70 or 75. I torqued mine to 60 ft-lbs. as the ARP instructions suggested - 18 months/10K miles ago. Note - that torque spec is for moly lube. If you used oil, I'd definitely leave them where they are. For some reason ARP doesn't list a spec for aluminum heads and threads lubed with oil, but if you interpolate their other data, they ought to be around 70 on aluminum heads threads lubed with oil.