She called back again to correct herself that this will NOT be escalated.

She said with vigor that she has reviewed everything, and confirmed all of what she said and also (this is worth noting):

"Class R is used for sticker upgrades from Main Cabin to Premium Economy."

I can only conclude, at this point, that the policies, if read to the letter, remit upgrades from Main to Only PE on flight where PE is sold, charging stickers.