Yes, it probably would.Also, at cruise my plane is almost 3 knots slower with the left light down. Would I be 6 knots slower with two down.
Back in 1985, I got my multi rating in a 1957 Cessna 310 down in Florida. I did all the training during the day, so I never experienced night flying in the plane before I took some folks on a trip to New Orleans from Crestview, FL. This was a mistake. On the return flight, it was dark. I took off and retracted the gear and flaps. I turned off the landing lights, but never retracted them into their respective wings... It took me a while before I figured out why I was cruising 30 m.p.h. slower than on the flight down. At one point the controller asked me if I was a twin engine Cessna. Once I retracted the lights, she went from 155 to 185! There was also the sparks from the over-wing exhaust, but that was another story...
The next morning, I mentioned the incident to the person I rented it from. He said it was common to use the lights as speed brakes to slow down from cruise!