Size. The aggregate size (sign area) allowed for all such signs on the lot shall not exceed 5% of the front facade of the principal building on the lot. However, in the event that there is no freestanding sign on the lot, the aggregate size allowed for all such signs on the lot shall not exceed 7% of the front facade of the principal building on the lot. The maximum size (area) of a permanent wall sign shall not exceed 24 square feet. If the B-1 District is in Stewartsville, the maximum size (area) of a permanent wall sign shall not exceed eight square feet.