Can't you set something like a Service Interval? The problem with many Closed Loop systems is that @ Idle the gas speed is low and the CL Intergral might have changed Fuel but hasn't measured the change back through the O2 sensor when it goes through the next change.
On my ECU I have 3D mapping over Service Intervals for the Closed Loop feedback. I make a large Inj. ms change manually and check from the LOG how many ms. it takes for the O2 to measure that change. This is the time I used for Service Intervals at IDLE. As higher the revs go the lower Service Interval time can be due to higher gas speed.