You can't. There's no way to disable it or change it back or format the numbers in the older (more sensible) way at this time.
I am a big fan of precision -- but if it comes at the cost of increased traffic to my client AND there is no way to round that .001 precision to 0.1 or even whole numbers -- then I am not a fan of the implementation and extra forced visual clutter in my UI.
Seriously? You guys are all worked up over this kinda cool change to make 46 posts on it? Its official ... Everquest players will whine about everything.
If you could not do wanted you wanted or needed to accomplish, then why was this done? As it is, it messes people's displays up. The only positive I've seen is the XP percentile being useful. The logical thing would be to keep the XP percentile and revert the rest to previous settings (until you can do the NPC HP % you wanted, and leave it at NPC HP % and not PC HP %).
If this is part of ANY traffic, instead of being calculated by the client, then you're doing it wrong in the first place.
It seems like they are updating something gradually for a future upgrade of something. The put all those decimals and different visual on plat on merchants and in baz and then they consolidated the loyalty tokens and put them in with regular alt currency and took them off their own tab and now these h/m/e % - another decimal change.
You're thinking in the wrong direction. The client isn't calculating damage. It's receiving updates. Mob takes damage or regents, calculates the percent of health remaining. Notices it is 1% less than before so it sends a signal to the clients to update the display. This happens say once every second. (for this example) Increase the Mob HP to show .1%. Now mob takes damage and sees his health is 0.1% less than before, so it broadcasts a signal saying "update my health display". This would happen 10 times as often as it did before (maybe not quite but potentially that much). Toss in regen mechanics that might heal a mob 0.1% on the next tick (which would normally be hidden by the 1% update) and it could be generating even more traffic than the quick calculation above.
I like the new decimals. So often I find myself in situations where a number of kills are needed to raise the level by one whole number; these decimal portions give hope. (I cannot read the progression of the central dark bar well.)