Our garments are hand crafted. During the hand cutting and sewing of the fabric we allow a tolerance for the workers. We list our tolerances on our spec sheet which details the range the measurement can vary. We then inspect our goods to make sure they are within the tolerance.
Example below shows the "TOL" (tolerance) is 1" on the Front Body Length and 1/2" on the Chest Flat measurements.
So, for this example on size Medium¬
Spec for the Front body is 28 1/2"
Then the tolerance can range from 27 1/2" to 29 1/2" of the actual garment
Spec for Chest Flat is 20"
Then the tolerance can range from 19 1/2" to 20 1/2" of the actual garment