Confusion on profession crafting screen

I'm leveling alchemy but this goes for any profession at any level
Why if I'm lvl 13 right now does it say:

"Increase potion level [Lv. 1 to 3]" when hovering over the top arrow, Then under that it has a checkmark saying: "Lv. 8 to 10"

But on the craft checkmark it says it's going to craft a potion Lvl 7.0 to 9.0?

What number correlates and means what, its really convoluted.