That's what I've been doing. The purpose of the spreadsheet is to avoid having to refigure ratios every time I decide to change the SWG setting or pump run time. For example, I've been running at 100% for 4 hours for the last few weeks, but I've been gaining gradually and I'm now at 9.5 PPM of FC. Not crazy high considering my CYA is >100 PPM due to goof on my part. (I'm not worried about an algae bloom, though, and it seems to actually be decreasing overall FC consumption as compared to last year, when 100% SWG for 4 hours/day was just about right on.) Anyway, I dialed the SWG back to 90%. It's easy enough to calculate the ratio every time I do this, but the pool calculator values are rounded to the nearest 0.1 anyway, so I'm calculating a fraction of an already rounded number. Hope this all makes sense.
In short, I'm well aware of pool calculator and have used it quite frequently, but I'm searching for more convenience and precision with my personal spreadsheet. Most folks just want to see pretty, clear water. For a math nerd, though, it's fun to calculate average daily FC consumption, which I can't do very accurately (or precisely) unless my input values are accurate (and precise). I didn't share my full-blown spreadsheet, but only the sheet I just added.