A common error when changing your Supercharger oil is to think you need to remove the drain/fill plug and fill it to the threshold like you would in a differential or a transmission. That’s wrong. The correct oil level is approximately 3/4" below the threshold of the drain/fill plug. Filling to the threshold of the filler plug could lead to oil seepage when the unit is turned off.
The proper way of changing the oil in your supercharger is to remove the supercharger from the car, remove the drain/fill plug, and the tip the supercharger up on its nose for an hour or more. This will evacuate all the old oil from the supercharger. Then refill it with 100 ml to 110 ml of supercharger oil and replace the filler plug.
Service kit includes Oil and Filler Plug
Article on Filling your Supercharger