My older Singer machines have directions that say the bobbin turns counter clockwise. They are top loading. My Bernina directions call for the bobbin to turn clockwise. The bobbin loads from under the machine.
The Bernina repair man told me this and in all my great wisdom I told him I had never put a bobbin in a machine to turn clockwise. Then the manual came out to check the directions. His reasoning was that the tension is better if the bobbin turns clockwise on the Bernina. It seems to sew fine either way so would guess the Singer would also.