Better method than the "1 inch per gallon" rule?

[grimlock3000]

http://www.geocities.com/scalehead/stocking.html

I came across this link in another thread and it seems very interesting. It yields much different results than trying to adhere to the standard rule of how many gallons of water you have and the lengh of the fish. It takes into account the size range of the fish, and detemines how much surface area is needed to support a fish in that size range. For example, I am overstocked on the 1 inch per fish rule (and wanting another tank), but I still have room for another few fish following these guildlines (not like I want any more fish for now)...

10 gallon tank: 20 length x 10 width = 200 square inches to work with

Guppy:
2 max length x 6 x 1 fish = 12

Tetras:
2 max length x 6 x 4 fish = 48

Dwarf Gouramis:
2 max length x 6 x 2 fish = 24

Peppered cats:
2.5 max length x 9 x 2 fish = 45

Oto cats:
2 max length x 6 x 2 fish = 24

Only 153 square inches of usage