Ignoring my own Apps for a minute. I've retried the Sensor Example project on my new phone running 4.4.3.
The magnetics sensor reports back, X=0,Y=0,Z=-1,541,952,432,780,780,000,000 regardless of actual real changes in magnetic strength.
This is the same issue that appears to be tripping up my own app.
EDIT: I am using Phone v2.25 if this makes any difference..