O2 sensor suspected bad

[kr4mo]

I just checked a friends 2004 R1100S and the O2 plot didn't look right. It stays at the lean and rich limits for too long (my opinion)
I've never seen this type of response on any other plot, most are sharp up and down swings. This one stays at the limits for as many as 5 of the time periods (dots). 
Anyone have this happen or any advice. I told him if it were mine I'd change the sensor.