My home has a hip and gable roof with ridge vents, for one gable end there is 25' of soffit that vents at 6 square inches per foot, so total venting for that gable end is 150 suare inches, BUT between the soffit and the interior of the attic there is only a single 3 inch square hole through the seathing that was made with a hammer. The same was done for all the other gable and hip ends. Now if I open my garage door 6 inches and then lower the garage dropdown ladder I create a draft throught the opening in the garage ceiling to the ridge vents. I think this may be due to the fact that the soffits don't have enough venting into the attic. Is this the case, and can I use a hole saw to cut 2.5" diameter holes through the sheathing on the inside of the attic to the soffits so that the soffits have the proper amount of venting into the attic?