This is a variant to make better use of your ability scores increases, without any real added power.
- At Character Creation if you end up with an odd number of odd ability scores, you can add +1 to your lowest score to have an even number of odd scores.
Ex: If you finish creation with 17 16 14 10 10 8 (one odd score) you will add +1 to your lowest score and get 17 16 14 10 10 9 (two odd scores). Just remember that "odd odds" is bad...
- At 4th level and 7th level, you add +1 to three ability scores; at 10th level, you add +1 to four ability scores. You cannot raise an ability score above 18 more than once per tier.
Ex: you can take your scores 17 16 14 10 10 9 at 4th level and add +1 twice to 17, since the first +1 brings it to 18 and the second brings it to 19 (raising it above 18), but you cannot do it a third time to 20 since this would be raising an ability to a score above 18 more than once.
Reason to be for those that care
The core system design (3x +1 increases to three different ability scores per tier) forces you to decide on all your increases at level 1. If you deviate from the ideal path you will finish the game with unused +1's (since odd scores doesn't change your ability mods). Even if you take the best possible path in the core system (3 odd scores at level 1) you will probably have no ability mod change at level 7, making the level feels empty. This variant doesn't make it impossible to have "empty tiers", but it is your choice to have at least one ability mod increase at each tier.