Time Warrior Greatsword Mastery

Does the skill works right? Adding skill points to this I dont get the expected progress. In Lvl 4 the skill will give me by reaching lvl 5 1 bonus point and for lvl 6 2 bonus points. If I add 1 point I get the 1 point for lvl 5 and lvl 6 changes to 1 point.
Is this right?
I have pictures but cant upload them.
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