Man, I used to crank those clamps down tight thinking it was better. Then I saw what @haydenmurray said about the low torque wrench and tried it. Now I get why the manual says that, it really does save the threads.
Sticking with a torque wrench set real low is what saved me. Like @tara642 said, those threads strip way too easy if you just crank it. I used to go by feel and wrecked a couple clamps before I wised up. The manual isn't joking about that 10-12 in-lbs range, it feels like almost nothing. Now I just snug it up to spec and never have leaks or ruined parts.
Actually that spec is right but the tricky part is using an inch-pound wrench, not foot-pounds. Lots of guys grab the wrong tool from their box and don't realize it until the threads are already gone, lol. I've seen it happen a bunch, the click on an inch-pound wrench feels super light. Just double check you didn't grab the bigger one by accident.