Yes, you can increase the number of licenses any time within the license period.
Additional licenses, purchased during the first half of the existing license period, will be priced at the difference between the total current cost of the original license pack purchased and the total price of the new license pack.
Additional licenses, purchased during the second half of the existing license period, will be priced at 50% off the difference between the total current cost of the original license pack purchased and the total price of the new license pack.
Additional licenses can be purchased through the AVG Upgrade Center.
NOTE: AVG Technologies reserves the right to charge the minimum order cost.