12.7% of 30g is 3.81g. KA rounded up from 3.81g to 4g for the label.
Labeling gives you an entire gram window for rounding. 2.5 to 3.49 is 3g and 3.5 to 4.49 is 4g*
Normally, nutritional label protein quantities are not the way to calculate protein percentage, but, based on the regulations, we now know that the Sam's bread flour has to contain between 8.3% to 11.6% protein. Even at it's maximum, 11.6% is too low for pizza.