From Ngreth at https://forums.daybreakgames.com/eq/index.php?threads/locked-out-zones-tov.261105/page-3 :-
While making the ToV mobs easier, one of the changes we made will have the side effect of making RoS, And TBL mobs easier. The big change is in the strike through number which (before we changed it) grew through those expansions. The change is based on NPC LEVEL more than the expansion the NPC is in, so EoK will be small to negligible change (*maybe* some of the higher level rares will be easier, but not much change will happen, and it may not be noticeable) while RoS and TBL will see a larger change.
NOTE this is ONLY a change to "group" base-pop and rares. Raid mobs are unchanged and still have an effective 100% strikethrough.
This is *NOT * a change to spells on the NPC, so the spells will be as difficult as they are. This only makes a difference on the melee damage they do.
This change will go live with the Expansion patch.