I'm going with what Tanuki said. I have reused mine several times. And I've never read where they cannot be reused.

But I used the right torgue off 34 Nm. I used my torque wrench which gets maintained and calibrated every year and I meauserd the torque after I ripped of one stud. The torque wrench made "click" by 36 Nm. 2 Nm more than hanyes manual says about "R" model NC29´s. So why do the first 4 studs felt so "doughy" when I tightend them and why got number 5 ripped of. I´m a mechanic for engines for Caterpillar and I got that feeling in my hands to know when a screw feels strange by tightening it.

34nm does sound quite tight tbh, you sure its the correct torq!?