Actually each point above 8 costs something off a little table, not so much 12 points to spread... typical spread is 27 points taken off the table I include down here.

ABILITY SCORE POINT COST
Score Cost Score Cost
8 - 0      12 - 4
9 - 1      13 - 5
10 - 2     14 - 7
11 - 3     15 - 9

By my calculations you got 0 + 9 + 2 + 4 + 4 + 9 = 28 meaning you're over budget by just one point.