6550C vs KT88

Thank you John, I took my unit back to the local dealer, they had talked to ARC as well, KT88 is ok to used in VT100 MKII, not MKIII. Instead of replacing the resistor myself, I trust ARC more in their QA and listening test. I decided to go with MKIII update, hope I had made the right choice. BTW, I'm testing my quad matched Svetlana KT88 in a friend's tube tester, just want to make sure they are OK, since my new MKIII can't use them, I would like to sell them (less than 5 minutes used). Let me know if anyone is interested. Thanks again

Thank you all for your feedback.
Last night, I replaced the 6550 with my new quad matched KT88 in my Vt100 MKII. I was using PS Audio P600 power generator as the power source. As soon the VT100 is switched on, I saw the wattage meter on P600 keep going up pass 400 watts. Normally it should settle around 350 watts. Before I had a chance to check for bias, one of the resistor on the left channel closed to location V2 just broke off (the insulation part only). The smell was pretty bad. I have no idea what just happened, only the left channel (both right and left are biased very closely) had this problem. Is it my new KT88?? or just a bad resistor which could not handle the higher voltage??