Sorry it's taken me a bit to respond to this... the past few weeks have been a little hectic.

Originally, they used to send raw XP numbers and the client would turn that into a percentage. As far as I can tell, they're now sending just the percentage that you see in the window, and all calculations for display are done server-side.

I don't know if ZEM is still sent, but if it is, it's not where it used to be in the stream because the values displayed by SEQ are obviously incorrect. I sort of doubt they're sending it, though.

Regardless, it should be possible to log exp values across zones, and compute effective ZEM once enough data is collected. For example, if you kill an even-con mob in one zone and get x%, but then kill an even-con mob in a different zone and get y%, those zones obviously have different modifiers. If we can do that in enough zones, then we should get a feel for what the baseline is, and an idea of what the modifiers are (in relation to the baseline) for various zones.

If we're really lucky, we might be able to use that data to find that they are indeed still sending ZEM in a packet somewhere, in which case we can make use of it. Otherwise, we can just alter SEQ to collect the necessary data and do the calculations, and/or compile the data and hardcode the ZEM values for the various zones. Except for hotzones, I don't think they change all that much.

If you (or anyone else) want to do some experimentation, that would be super helpful. Zone name, your level, mob level, xp per kill, and whether it's XP or AAXP would be what we'd be looking for, I think.