It's 3 and 5 actually, but it will show as 4 and 6 because of the "little green dot" function. If you extend your skill bar, you will see them on top of each bar, put or remove dots (depends which style is more comfortable for you) and the 'V' key on your keyboard will switch between those bars with a green dot and ignore the ones without. That's why it shows 1 more, that's a actually the first one.