It would help if you post a picture of that number.

If you filled the radiator to the very top I expect that there will be quite a bit of coolant expelled.

The coolant expands as the engine gets hot. After it has overflowed a couple of cycles it will be at the level you should maintain.

Most of the time the proper level is enough coolant to cover the radiator core. The upper tank will be empty when the engine is cold.