The math is not wrong you are assuming everything is linier and it's not.

It's just an average and yes the math does work out. Hoods absorb heat and reflect the light back down. Hoods are with in the 12" window of all power being considered the same so hoods don't absorb the light.

The math say's percentage of light that hit's the Mylar is reflected back when you start to add up all the lights yes it does add up that fast. You read like my wife you add conjunctions and words to make statements fit what you are thinking in your mind when you read it. Take it for what it says and try not to read into anything. The math is true and correct.

"With Mylar you reflect back 98% of the light that hits itâ? key word "light that hits it"

I did not say how many plants were in the room its just examples of how well Mylar can reflect the light. You are making assumptions on your own but if you take it as it is written then it's correct.

The number of your plants in the room will affect how much is reflected as well as the density of the plants and the size of the plants. There are way to many variables to calculate to cover all grows so it's acceptable to use best-case scenario with out plants or anything else to block the light.

That is an FAQ on why you should use Mylar. Side lighting is just lights on the sides of the plants.

I hope that cleard things up a bit for you, but thanks for asking.