Maybe I'm horribly behind the times and you already know about this, but I must share a new-to-me tool that has saved me a ton of time.
If you're a self-published author and you're trying to figure out how to read Amazon's sales reports, you really need to sign up for Book Report. Especially if you're on Kindle Unlimited and you're trying to figure out those pages read.
Book Report will pull up all your data and tell you within seconds how much money you've made so far that day and how much for the month. It shows you on a pie chart which of your books are selling the best that day, and it also shows you on a line chart how your sales today compare with your sales for the rest of the month. And it's only $10 a month.
First, go to www.getbookreport.com. You can try it for two weeks to see if you like it, and they won't even take a credit card for the trial period. Sign up and bookmark the site. Then go into your KDP sales chart as always, click on the bookmark, and Book Report will pull up your information. Poof! There you are.
You will need to go into the settings tab on Book Report and give them a figure for pages read. It's been fluctuating between .0047 and .0049 cents per page, so I keep mine set at .048 just to give me an average. That's the only thing you need to adjust - it will pull all the rest of your prices, etc. from Amazon and calculate your royalties from there.
There you have it - one of the coolest gizmos ever. And they didn't even pay me to say it!