My immediate thoughts are that there are just too many parameters governing the running and maintaining of a planted tank, to be able to make a simple chart/calculator/program.
I'm not saying a program couldn't be made, but I'm suggesting that to cover all variables, you would have to make it very complex and even then, I'm not sure about it's accuracy. There just isn't enough scientific research to precisely say how a tank will react to minute levels of nutrients/parameters. For example, when we dose the fertilisers into our tanks, we are going on the grounds of tank size, amount of lighting and CO2
in general, but there are finite variables to consider such as type of plants in the tank, their natural habitat, how many plants, how many of each species present, how densly planted, age of plant, allelopathy, competition, position, height, fish interaction, type of lighting, spectrum of lighting, age of bulb, height of bulb from water....... the list goes on! This is why even a dosing plan like the Estimative Index that works quite well, still needs a relatively large water change each week to "reset" the tank to account for these errors in calculation.
Every single tank is different in some way.... lets face it, if we all had a system to follow that worked so well, none of us would be here on this forum!
I don't mean to extinguish your flame of inspiration, I personally am all for computerised programs and scientific analysis wherever possible, but I think you are being a little too ambitious here.
p.s. I am reading through Ecology of the Planted Aquaria at the moment.... it's an excellent book!