I asked a pal of mine the exact same question, he is a CPL and used a twin Squirrel every day, he passed it over by saying he had never really tried to work out why, but he went on to say, it did make you look a little under-experienced.
But yet I watched an RAF FI and student land a single Squirrel and never saw the same wiggle, could it be big engine covers create dead spots when trying to come down slowly?
Vfr