Newbie problems with first project - 3 part data field

I have been playing with the SDK and built a 3 item datafield to display HR (data1), Distance (data2) and Cadence (data3). I based it on the 0.2.4 ComplexDataField sample.

Heart rate works great - updates consistently, in step with the Garmin Heart Rate field

For distance, I just want full kms (similar to 1km auto-laps) - tried int(info.elapsedDistance). This doesn't seem to advance from 0. Maybe a scaling factor?

Cadence is where I am having a strange problem. It only updates sporadically and holds the value for minutes at a time, then randomly zeroes or changes. This is despite the fact that the stock Garmin Cadence field is being constantly updated. My field is not keeping step in reflecting those changes. I think info.currentCadence is the correct - just not sure why it isn't changing regularly like the Garmin field does.

Can you please take a quick look and see if I'm missing something fundamental?

I am using a vivoactive on FW2.80

function compute(info)
{
var info = Act.getActivityInfo();
//Get data1 if valid
if( info.currentHeartRate != null )
{
data1 = info.currentHeartRate;
}

//Get data2 if valid
if( info.elapsedDistance != null )
{
data2 = int(info.elapsedDistance);
}

//Get data3 if valid
if( info.currentCadence != null )
{
data3 = info.currentCadence;
}
}