XMAN,
Yhbae does not account for plants because he is afraid that the inclusion of plants may result in a condition in which the aquarist might not have to do water changes (and water changes should be done regularly, even if the water chemistry seems fine). Another problem with adjusting for plants is that it is hard to find solid data that can account for how a plant interacts with fish waste byproducts. As far as I know, my spreadsheets are the only stocking calculator on the web that account for plants. I, however, cheat a little in that my formulas are not species-specific but instead use the plants' growth rate. It is a complicated formula yet has worked well so far.
Rbishop,
The calculation is probably correct--what makes the difference is how you interpret the result. The basic question is whether or not you agree with yhbae's operationalization of what is "ideal."
The reason why I bring this up is that I kinda hate to see a formula be blamed for what is really more of a personality/belief issue. In other words, not agreeing with the result does not make the underlying computation wrong. Contrarily, it means that the users may simply disagree.
Cheers,
MOA