It's a good point. The justification for this particular item having XI was in comparing items that already drop in T7 Dsk, though:
http://www.thehiddenforest.org/webtools ... p?id=83598http://www.thehiddenforest.org/webtools ... p?id=83504Two examples. I think this might be a wider issue that predated my involvement as a content developer. Looking at examples of items that have the IX tier of effects shows items from T5 and the X tier exists on T6 stuff.
Logically, T7 ended up with XI. So it's unclear why T8 items have X.
But I wasn't around when the T8 items were created so can't vouch for the logic behind choosing X instead of XI. It could be an oversight or it might have been deliberate.
Will discuss internally.