Welcome to TFP!
There are quite a few reasons why we have settled on this process for killing algae over the years. Chlorine decays on a percentage basis, not a ppm basis. So, you don't lose x ppm per y time you lose x percent per y time. There is potential for bleaching pigments in plaster or vinyl, causing liner damage and problems with pool equipment. There are also potential problems that you could see by frequent early testing like antifreeze or ammonia in the water rapidly consuming FC. And there is years of evidence that these FC levels kill algae just fine in hundreds or thousands of pools every year in a reasonably short period of time if the process is followed diligently.
More, often isn't better. A sprinkle of salt on a steak is good but a pound of salt on a steak isn't better. :chef: