I have 2 Donnay XP Dual 102's. One is a 4 1/8" grip with a 10.4 oz weight (unstrung) and 320mm balance. One is a 4 3/8" grip with 10.6 oz weight and 315mm balance. Both have the above specifications printed on the racquets. Question: Is the different weights and balances due to the different grip sizes?