Okay ...
Let's say:
You're level 50 ... and your warrior mastery is at lv.45 ....
You have rogue mastery on lv.40 ....
Your highest mastery is warrior mastery and that makes
5 gap .... (Level - Highest mastery= 50-45 = 5)
Overall mastery doesnt mean anything ... you just look at highest
mastery and your level.
1 gap = 10% more sp
2 gap = 20% more sp
3 gap = 30% more sp
4 gap = 40% more sp
5 gap = 50% more sp
6 gap = 60% more sp
7 gap = 70% more sp
8 gap = 80% more sp
9 gap = 90% more sp
9 is highest gap ... I mean you get most sp then ....
If you have 10 gap you will get same amount of 9 gap.
Hope I helped

You wont have enough sp to waste it on all skills .. meaning if you dont
have gap you wont be able to get all skills ... there will