Thanks for the tests.
The thing is Excavator is by far the fastest while doing Neoscrypt, so I can't use anything but that. And I have no issues with Excavator on AHashpool, Altmier, Zpool and MPH.
So there is something to be sorted out between the the communications between your Server and Excavator.
Same here. Excavator gives me a 20%+ increase in actual hashrate on other pools (Zerg, AHashpool, Zpool, unimining.net, MPH and many others), so they must have done something to make their stratum "compatible", perhaps specific to NiceHash (since that is what excavator is designed for).
Not sure if the 1.4.4a release changed anything, but I can't afford to use the slower clients you mentioned.