Alternate Pathfinder Point Buy System

I've always struggled with the choice whether to use the tried-and-true "Roll 4d6, Drop Lowest" method of ability score generation or the "point buy" method. I like the random elements of the former, but I also like the balance and control the latter offer. I usually end up using the random method because it tends to be faster and I've never been too fond of the way Pathfinder's point buy works.

Recently, I've been toying with a point buy system for Pathfinder that will hopefully be faster and easier to use. When using this system, each ability starts with a score of 10. The player receives a pool of points they can spend to raise these scores. They may also lower their scores to gain more points to spend. This is done on a 1 for 1 basis. No score may be raised above an 18 or lowered below a 7. The number of points is based on the power level of the campaign, as depicted on the following table:
 

Campaign Type	Points
Low Fantasy	6
Standard Fantasy	12
High Fantasy	18
Epic Fantasy	24

Personally, I've always felt that point buy systems that use a 1 for 1 price scheme are much easier to use than point buy systems that give each score a specific price (i.e., a 14 costs 5 points, 15 costs 7 points, etc.).  This method also allows you to use the system without having a specific table because you just have to use some basic addition and subtraction (Exp: spent 6 points, raise a score by 6 points).

I'm also thinking about adding a optional variant for this system called "Focus & Flaw". Before spending your points, you designate one of your abilities as your "focus" and another as your "flaw". The focus ability is one that you are particularly adept in, while the flaw ability is one that you are particularly weak in. Instead of starting with scores of 10, the focus ability starts with a score of 12 and the flaw ability starts with a score of 8. This would mean it would cost less points to raise your focus ability, but it would cost more to do the same for your flaw ability.

While I do enjoy randomly generating ability scores, I might just use this method for my next Pathfinder campaign (probably with the Focus & Flaw variant as well).