Alternate Point Buy Chargen for B/X D&D

I've previously written about non-random character creation for OD&D / Swords & Wizardry, but lately I've been thinking about running a B/X style game again via G+ Hangouts and wanted to have an option for creating characters without needing any dice rolling.

Similar to the option for S&W this system is based on keeping track of the ability score bonuses and penalties. Each character begins with 1 point which represents a +1 bonus or *13* in an ability score. All other ability scores have no modifier and are assumed to be a score of 11. For each ability score penalty point a character takes, they may take an additional bonus point as well. So if a character had an ability at 7 (-1 penalty) they could take an additional attribute at 13 (+1 bonus) or raise their 13 to a 16 (+2 bonus).

Here are the ability scores and their bonuses or penalties when using this non-random system for creating characters:

3 * -3
5 * -2
7 * -1
11 * 0
13 * +1
16 * +2
18 * +3

An example character using this system would be:

S 18, I 7, W 11, D 13, C 11, C 5

Update: Thanks Joe, my bad math is corrected. :)