First off if you have two bolts made of two different materials with different elasticities and you torque them both down to the the same spec, they will exert the same amount of force on the surface they are being applied against. You might have to turn one more than the other and the amount of stretch may be more but if they are both tightened to 25nm they are exerting 25nm of holding force. Second, yes you want to make sure you don't crush the races but you're talking much higher torque specs before you need to worry about that and unless common sense escapes us all, people know you don't keep cranking on a bolt that holds down a bearing. If you don't, you shouldn't work on your car.
