Level of GW enemy squads ONLY based on Arena power? Don't think so!!

RoJaGiTa

I read a developer say that the level of enemy teams in GW is determined by the highest power total that your team ever had when earning an Arena victory. My recent victories in Arena have been with 11,000 teams and I've made sure that, as I've upgraded my characters over time (now have max power team of 15,000 that I use in GW), my Arena team continues to win with a max power of 11k. In theory, this should mean that as my GW team gets stronger and stronger, the GW enemy squads would still be determined on the basis of my Arena power of 11k. I've been analyzing the data the last few days and this doesn't seem to be the case (i.e. other factors are being used to determine level of enemies). Some data showing total power of enemy teams I've faced during last 6 levels of GW:

Sun- 12,106 / 12,849 / 15,462 / 13,525 / 13,509 / 13,428
Mon - 13,302 / 13,069 / 13,251 / 13,938 / 15,788 / 14,025
Tue - 12,750 / 14,823 / 14,216 / 14,208 / 14,226 / 14,181
Wed - 13,152 / 13,809 / 14,363 / 14,373 / 14,618 / 14,425
Thu - 13,131 / 13,904 / 14,636 / 14,633 / 14,654 / 14,650

The level of difficulty appears to be increasing over time, and I wouldn't have much chance if both my GW and Arena teams were both at 11k.