Yes rocking one or two times a minute is fine. Have you had a boil over inside letting juices flow out of a jar? Make sure your exhaust spout and weight are very clean and shiny again. I have the same cooker as yours this stuff from a boil over turns into a varnish and is sticky as all hell when hot. This has almost stopped my rocker from rocking in the past.
I just cleaned it up very well even used some light sandpaper 400 grit to get the shine back and it stopped.