I have 3 or 4 bobbins that came with my Featherweight. I have purchased some more bobbins from two places, both reputable and the newer purchased ones are slightly 'shorter' than the ones that came with my FW. I remember reading somewhere that original bobbins sit slightly taller than the bobbin case itself and the 4 I got with my machine do this. The newer ones sit more flush with the top of the bobbin case. Is this the way the newer reproductions work? If so, are there tension issues common with the newer, shorter bobbins?