As i understand it, the reason for the asymmetry of the blades (long top edge, short bottom edge, when held right side up) is to promote a smooth and flutter free entry and exit of the blade in the water. Once the full blade is in the water during the power phase, the shape doesn't matter so much.
So i think the feeling of more torque you felt is probably due to the higher angle of stroke you mentioned. But if turning the paddle upside down gives you that mental edge, i say go for it!
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Touring Kayak Paddles