Biosphere was supposed to provide an actually good leveling spot for the 240-250 range, yet what we got is worse than dungeons we had prior to the update. I keep track of exp gain per BM when leveling, so for context:
Level 240 Comet Arch Mage with Mental Sensing, VIP + 3x BM, +30% Exp costume, no weekend event
Ice Biosphere: ~5.5b exp/BM
Amicitia2: ~10b exp/BM
Meanwhile, over on twRO:
Level 242 47.1% -> level 243 13.5%
which is roughly 46.5b exp/BM
but for some reason, everyone seems to be preoccupied with snorting Ether Dust to care about that
twro updated level cap 260? may they have different exp requirement from 242-243.
iirc, kro/twro had an updated that promoted mobs maxhp for 5 times, and also promoted drop rate for materials like ether dust, shadowdecon, zel, dont know if they also promote the exp. This update applied to amicitia, nif_dun and biosphere.