Since early April we have had repeated problems with dispatch lag, that required quite some manual intervention. This started on April 9 (which also is the day where ff4db0c87156035d79c0378ab8ba0aa2045ecf27 was merged).
As can be seen in the graph below, the mwscript switch to hhvm seems to correlate with a significant increase in the median pass time:
(the last increase here is probably due to a change in the Wikidata edit pattern over this weekend)
Due to this I suggest to raise our resources for dispatching by up to 60%, since the median dispatch time also increased by about that (from maybe 1.4s to 2.25s).