Calibration measure reports bad values when only one bill

[macumber]

Electricity Consumption (kWh)

CV(RMSE) =0.0
NMBE =0.0

Start 1/1
End 1/30
Actual 10
Model 135
NMBE 1,247.23%

[jmarrec]

This is really a user error, if you're trying to fit any model with only one datapoint, but I suppose some error/warning would be in order. (and maybe it is already in place)