I was just trying some options about modding and used the Relentless Precision Neck Mod to get more Prec. Escalating Might is working as intended BUT Relentless is not. I tried to hit sparring targets 9 times, 10 times, 11 times... a lot if times... and my precision did add up 170, as described in the neck mod tip. Pressing F1, you can easily see when Escalating Might is active, giving you, at least, 87 might... Nothing appears using Relentless Prec. I tried in Test Server, same thing. Or I am doing something wrong or it is a bug.
Sparring targets dont give you a combo meter is why .. There's a feat for 100 hit combos... And they don't want people getting it on a test dummy