I think it is. The larger the pad, the harder it is to control it, the more it fatigues you and the more work you have to do to get the product you're using to break down into the paint. It also tends to sling more as well. The larger the pads, typically the slower the speed you will want to use. If the recommended setting for medium is a 5 of 10 on your machine, you'll want to use a 3 or 4 because the larger the pad, the faster the outer edges of the pad are moving compared to the center. Unless you're using Griot's products like you are for now. They give recommended speeds on their products based on their buffer.
Did your machine come with a 10" backing pad? Can you swap to a different size backing pad? If so, I would shoot for a 4"-6" maximum pad diameter.