It's worth noting your method, bwana, that your method eventually becomes 1 point per 25 levels as well. Imagine all 508 of your pets were 25. Adding up all the levels would be essentially 508*25. Dividing that by 25 would give you 508 points, which is exactly one point for every level 25 pet.

Currently levelling provides about a large % of your pet score if you have a really small collection but a really small % of your pet score if you have a really large collection (about 3% if you have all 615 pets).

With your method it would be more stable, which I like. With the max sized collection, levelling would max out at 16.667% of your total pet score.