A licensed public weighmaster shall not enter on a weight certificate issued by him any weight values but such as he has personally determined, and he shall make no entries on a weight certificate issued by some other person. A weight certificate shall be so prepared as to show clearly that weight or weights were actually determined. If the certificate form provides for the entry of gross, tare and net weights, in any case in which only the gross, the tare or the net weight is determined by the weighmaster he shall strike through or otherwise cancel the printed entries for the weights not determined or computed. If gross and tare weights are shown on a weight certificate and both of these were not determined on the same scale and on the day for which the certificate is dated, the weighmaster shall identify on the certificate the scale used for determining each such weight and the date of each such determination.