Flew Hainan again last week, BRU to PEK.

The aircraft had a Premium Economy section of 21 seats. The agent told me this was a special situation due to an aircraft change. I bit, paying 210 euro for an upgrade on my P fare ticket. About 10 other people did so as well.

Other upgrade options were similar to 6 months ago.
Econ first row or exit row: 105 euros (down from 135)
Y/B/H/K/L/M to business class 700 euro
Other cheaper fare classes: 850 euro
O: 1050 euro