OK, I am playing with the placement of the sensor to see if that fixes the problem. I've commented out this section:
//SonarMote
sonar : { name:'CM', regexp:/\b([\d\.]+)in?\b/i, value:'', unit:'in', pin:1, graph:1, graphOptions: { legendLbl:'Level', l
ines: { lineWidth:1 }, colors:['#09c']} },
Also changed the metrics.js to "in" everywhere CM was, and it still shows CM.
//SonarMote
sonar : { name:'IN', regexp:/\b([\d\.]+)in?\b/i, value:'', unit:'in', pin:1, graph:1, graphOptions: { legendLbl:'Level', l
ines: { lineWidth:1 }, colors:['#09c']} },
I'm sure its a simple case of "you don't know , what you dont' know". And clearly I don't know!