No. Basically, at 55 your stats gain much less from the rating: in fact, most people suggest not having crit beyond 20% (pre-buff); bolster was bugged in a way that you could easily attain ridiculous crit chances beyond the possible ones at 55: 30% is actually the hard cap from rating at 55, and I would often hit it with bolster, whereas it requires ridiculous amounts of critical rating to reach at 55 (actually impossible even if you stack it as much as you can).

For the reset, make sure you hit him each time you go activate the defence systems. He appears to reset if you do not hit him for too long.