I would agree to not worry about THE number but I would also say that 60 rpm in the saddle is darn low.

My wife (neither of us are Clydes or Athenas) complains of knee pain and her issue is that she is a masher. I catch her up shifting all the time and I fuss up a storm over it.

It is true, some people are naturally mashers and with good knees and such, they can spin away at low cadence a lifetime but most people, including me and most particularly my wife, really need to be spinning much faster. The high spin rpm reduces the load per cycle on the knees and in particular the overloading of the joint. Think about it like this, take a coat hanger wire and bend it only very slightly back and forth really fast. You can bend it slightly back and forth nearly forever. Now bend it a whole bunch but very slowly and soon it breaks. So, this comes to my final point, mashers as an observation often have their saddles too low which contributes to their mashing and low rpm. Get your saddle height correct and work on spinning at a higher rate, preferably something well over 60 rpm and closer to 80 to 110.

Oh, let me add this, unless you are using toe clips or some other retention system pedals you will never get out of the "mashing" habit.

Also, if your butt is bouncing in the saddle, this is an indication you are spinning to fast and is especially exacerbated by using no foot/shoe retention system and low saddle.

Rocking hips, too high of a saddle, usually not the issue with mashers IMO.