[Dual-Blade] No Cash-Shop Mastery-Books = No 4th Job Dual-Blade?

I was bored so I made this heavy mutilated Dual Blade build, in case you don't buy Cash-Shop Mastery-Books:

1st Job (10~20 = 31SP)
----------------------
10 Double Stab
-> Save 21 SP's

2nd Job (20~30 = 30SP)
----------------------
10/10 Triple Stab
19/20 Mastery
20/20 Booster

-> Left over SP's: 2
0/20 Nimble Body
+2 => 2/20 Dark Sight
0/20 Disorder

===============================

2nd Job+ (30~55) = 76SP)
------------------------
20/20 Self Haste
20/20 Fatal Blow

18/20 Dark Sight

-> Save 20 SP

3rd Job (55~70) = 45SP)
-----------------------
20/20 Flash Jump
20/20 Flash Bang

5/20 Slash Storm (No Skillbook = Maxed @ lvl5)
5/20 Tornado Spin (No Skillbook = Maxed @ lvl5)

-> Left over SP's: 15
+2 => 20/20 Dark Sight
+1 => 20/20 Mastery

+10 => 10/20 Endure
+1 => 1/20 Disorder
+1 => 1/20 Nimble Body

===============================

3rd Job+ (70~120) = 150SP)
--------------------------

0/10 Bloody Storm (Not Maxed Slash Storm = Maxed @ lvl0)
10/30 Mirror Image (No Skillbook = Maxed @ lvl10)
5/20 Flying Assaulter (No Skillbook = Maxed @ lvl5)

20/20 Advanced Dark Sight
20/20 Owl Dead
20/20 Upper Stab

-> Left over SP's: 75

+10 => 20/20 Endure
+19 => 20/20 Disorder
+19 => 20/20 Nimble Body
+10 => 20/20 Double Stab

-> Left over SP's: 17 => No -POSSIBLE- place to put them into, -EVERYTHING- is maxed.

Conclusion:
Since you will have 25 left over SP's -forever- (untill you buy the mastery books), you're not able to put any SP's into 4th job skills, or even better: you can't job advance to 4th job... Fail Much Nexon? :')

Advise:
Don't start playing Dual Blade, unless you have enough NX to spend all SP's untill 4th job... :')

Edit: Corrected Double Stab to max to lvl20 instead of 10... still, 17 too much SP's to advance...