Dear Johannes, all,
Aaron confirmed that we are on the same nodes. So it must be due to the stochastic behavior, indeed.
Some of the new bounds are not trivial, BTW. You can filter with "new results" to inspect them: https://termcomp.herokuapp.com/Y2022/Derivational_Complexity__TRS.html?filte...
One could have a different mode for competition: output is a sequence of (true) statements BOUNDS(low,hi) (of nested intervals), and the last (narrowest) one counts. I think applications would prefer something like this as well.
Upper and lower bounds (or even termination claims) could better be given independently. But I'll wait until tool authors are motivated.
Best, Akihisa