Here is the explanation for each row on the table:
Total AP Required = The sum of the AP you need to spend to reach this Rank.
AP/Week = The amount of AP earned solely through Meditation every week.
Bonus AP/Week = The difference in AP/Week between Rank F and this Rank. In other words this is the Bonus AP from ranking up Meditation.
Weeks to Repay Total = This is the amount of time (in weeks) required for the AP that you spent to be repaid in full. (= Total AP divided by Bonus AP) e.g. approximately 56 weeks must pass for Rank A to refund itself.
Extra Bonus AP/Week = The marginal AP/Week compared to the previous rank.
[Image: http://i106.photobucket.com/albums/m274/Silverine13/M1.png]
The bonus from Meditation is slightly more favourable for Evies (average INT at Lv.38 is approximately 800. Source):
[Image: http://i106.photobucket.com/albums/m274/Silverine13/M2.png]
[Image: http://i106.photobucket.com/albums/m274/Silverine13/M3.png]
Hopefully these tables will be of help to you. The final decision is of course up to you.