I've been posting about this since August 22nd. I have been trying everything in terms of being able to "break" nodes and it isn't something I can do with any consistency. The only constant is that the teams I am matched up on are WAY out of line. I am not in the top 100 arena wise - never have been - never will be. I don't spend enough to keep up apparently. Bottom line - I was able to consistently beat the tables daily before - and then they changed the power ratings and I've cleared 4 tables since I've started paying attention. 4 tables since August 22nd (78 days figures out to a 5.12% completion rate).
Maybe they will fix it some day, else it'll be another day of node 11 wiping all my units out mercilessly.
Today's killers was a maxed out team of CLS lead, R2, Wiggs and Raid Han - so at least I got beat by a team that makes sense synergy wise for a change.