To the OP: If you are curious, the pattern scales regularly after reaching 14. You take the list above and add to it:
16 = 10
17 = 13
18 = 16.
Most DMs don't allow scores above 18, because that would be impossible on a rolled character as well. By the RAW, there is no benefit for taking a score less than 8, but a know many DMs who allow a score to be reduced by 1 to add 1 to the PB pool. Thus, in a standard PB of 25 by taking a character with an ability score of 6 (before racial mods are applied) you could use a PB of 27 for the rest of your stats. This is strictly a house rule, however, and should be understood that way.
Also, I don't know what your DM said - although I'd appreciate knowing! - but one of the most common misconceptions about PB is that PB starts at 10 and not 8. Thus, to be truly average and have all 10's you have to spend 12 points right there (2 for each ability score).