Before checking the level, I would advocate looking at the most probable cause for a leak - and that would be the front seal, immediately behind the pulley. If the SC is leaking from this front seal, the light SC oil typically snakes back along the underside of the snout toward the main body of the SC. With the engine OFF and using clean hands, simple feel along under the snout of the SC. This should all be dry. If you come out with a bit of oil on your hands, you may have some weeping from this front seal. Thankfully, these cases are rare. Assuming the underside of the snout is dry, I think that when you remove the black front allen plug, you get just a small ooze of oil coming out. This is perfect, and simply re-install the plug. Rarely should you have to add any oil but always good to check.