"Internal calculations found the total cost of headaches was $22.5 million a year"
Sure. Because you have all the required variables to determine the cost of a headache.
Although I am apparently immune to that scourge, I can see the effect a headache has on my wife, and I have a friend who is subject to migranes. Everyone knows that a powerful migrane means locking oneself up in a dark, silent room and suffering until it goes away.
That's not fun in any book.
But assigning a cost to a headache ? Come on, did you just tally the number of days taken sick and call it a day ?
What about people who have headaches but keep on working and don't say anything about it ? Some headaches are minor inconveniences, and I'm sure that, in a culture like the Japanese have, they won't let a minor inconvenience get in the way of doing their job. So, no cost there then ? They are still inconvenienced, they might work more slowly, or have to check twice. That's time lost, ergo cost, but you have no way of counting that.
$22.5 million a year is a large number, but I have a tendancy to file it with declarations of the "this virus cost that many billions to the industry" sort.
In the round filing cabinet.