O.k., I think this qualifies as a bug

The tool has a 10% margin to allow for rounding the label data. If ithe error is above 10% it gives an error.

The label data you enteres is within the error margin, so it should have been o.k.

But the error you got was because the data is normalized to 100 grams, and at such scale, the data was beyond a 10% margin of error.

To make a long story short Enter the calories as 77 instead of 80.

This is just a short cut to make it work for now, but I'll make a fix to validate the data based on the weight stated in the label, not for 100 grams.

Wa'il