Here's the main problem with the closed loop meter (even the a/f meter)... It reads directly off the sensor... Yes, there will be somewhat of a correlation between the sensor and the ECU's response - but not directly as seen with the SG and closed loop monitor not being in sync.
The ECU decides when it's in closed loop based on sensor data it gets. It's perfectly reasonable to say that there will be moments when the sensor data is just totally bad. So the ECU works within tolerances.
I built autospeed's closed loop monitor too
And I get the same results, the SG (which determines closed loop based on what the ECU says) and the monitor (which gets results from a wire tap) don't agree... The loop monitor fluctuates
BUT, when the SG says open loop, the monitor generally does too.