I wonder if it is feasible for a Techmarine to add his SB for the Servo-Arm to his total 'lifting capability' which is calculated by adding the Spacemarine SB+TB? If he have strong enough footing/balance, he should be able to take advantage of both his own body weight and the Servo-Arm?
In my example 10+10+8 would be 28 in lifting capability, what would he be able to lift with that?