Yea... I don't know why the two pics have a different looking float. I have not checked mine when its hot, for fear of burning myself! I always check it cold. I think that must be a mistake on the diagram regarding the float pic.
When I checked mine... I was kind of surprised that to find my coolant slightly low. I guess this is why some have their coolant light come on. I think our cars must use a little bit of coolant and oil - over time.
My only other tip is to make sure the cap 'clicks" when you tighten it back up.