Experiment on CP4 today:

Started at 90% full
Filled to well over 100% at 45% open on LLCV
At 12:10pm local, CP reached 100% full (took ~3 hr 40 min)
I sat at MY for about two hours with nothing happening (at this flow rate it takes a lot longer than 35 min. to overfill till LN2 comes out)
Finally I began to ramp the LLCV 5%, and then 10%, every 20 min. or so
At 72% open the signal from the flow meter was very noisy
After a few min. at 72% the exhaust pressure started to rapidly rise so I set to PI-mode with min. allowance set to 39% (love the new code!)
The pressure was still high and unstable and because I didn't want LN2 to spew onto the flow meter I lowered the PI-code min. to 37%
The exhaust pressure has slowly ramped back down to nominal
Leaving in PI-mode (at 37% min) over the weekend and will periodically monitor pump level and pressure