I'm not sure that the problem you think exists actually does. The program calculates the best item/town combination at that time. I'm level 9 in Taill, and it occasionally tells me to take heat crystals as opposed to anything else. This is because, as you note, selling large quantities of any item will decrease its price. But that's what this program is for, and it responds to the changes. The price drop would and does happen anyway, just because of people's common profit goals. Nothing can be done to avoid it.
Commerce prices only fluctuate every 10 minutes real time. This gives you a window to basically haul some ass to the town, before the prices lower. You can bet others will do the same. Once again, this is a nuance of the game system, and MabiCommerce really doesn't change it, for better or worse.
Profit information is as current as possible. When you select a town, profit information is immediately downloaded fresh from the server. That's what the slight delay is before items show up. When you hit Calculate, the new data is immediately uploaded to the server, and is thereby immediately available to other users. Because the webpage uses the same values, it will also be as current as possible.
Also, using TAB and the numpad, I can enter an items profits in about 5 seconds. How much faster do you need to be, esp when some/most/all values are filled in for you?
Well I've seen the price on Circle barrier spikes drop from 210 profit to 47 loss and I returned right after my delivery....
And curse your Excel spreadsheet! It wasn't very useful to me 'cause I don't have Excel D: (and I'm both too cheap to buy it and too uppity to..."acquire" it elsewhere).
Have you tried using OpenOffice, it's free and opens MS Office documents.
Here's an idea for this project. Calculate exp per route.
This sounds like a good idea... I still don't know how the exp is based....