LiquidAir I have the same setup. I run my Elizabeth at 198 degrees (92C) for moderately dark roasts. I use 6 seconds of pre infusion with the pump running for 3 seconds per Dave Corbey advanced settings. I use 16 in with 32 out, and it is very consistent with the Niche. I typically run around 32 seconds total. It is the same shot to shot, especially now that I do not RDT. Perhaps it is your puck prep? Furthermore, I am running drip coffee first, and then dialing the Niche down to the espresso range with no purge, and it is still consistent. My puck prep is pretty simple. Grind, invert the dosing cup into the portafilter, shake a bit, remove the cup, tap to even, no WDT, tap on the bench, tamp, and then brew. Very nice results. I also have a Trade subscription. I love it.