YES!!! Thank you! If that's accurate, I have another 3:15 to download any titles to my PC.
I just downloaded and installed Kindle for PC and Mac. What a BITCH installing it. First they want my password. My usual Amazon sign in won't work, so I get my PW and install it and I had to endure the worst let's prove it's you I've seen maybe ever. You know the kind, 9 rectangles, click the ones with beds, or chairs, or curtains. I went through about a dozen of those before it would accept I am who I say I am. Then I see my collection and it's about 100 titles. I downloaded practically all of them. Around 10 have limits, being can't install more than once, if you want to install on another device you evidently have to buy it again!

Anyway, I have some great great books. Lots of my books are self help books that were free and I've never even looked at them, but they have great titles. Most of those are probably crap, but some probably aren't bad at all.
Quite a few titles I have I've read and could read again. Many are famous classics I've never read. All on my PC now, and AFAIK all on my Kindle and presumably if they aren't on my Kindle I can download them anytime to my Kindle (Paperwhite Version 2).
I have had Kindles since 2011, the first a Kindle Keyboard 3G. That was relatively crappy compared to the Paperwhite I bought in 2015, which I'm still using. AFAIK the more recent ones aren't much better, not enough to warrant a purchase. My Paperwhite really is amazing. And I discovered this recently: Turn off Wifi and the battery lasts waaaaaaaaaaaay longer. The only reason to have Wifi on AFAIK is to download titles to the Kindle, which is something I only rarely do. Leaving the Wifi on appears to run the battery down even when you're not reading a book, i.e. when the screen goes to battery saver image. Only turning off Wifi actually stops battery drain, or close to it. Even with Wifi on, my Paperwhite has good battery life, but I sometimes don't use my Kindle for weeks and I'll open it and find the battery drained or close to it, so keeping Wifi off totally makes sense for me.
Um, I wonder if I have to do this all over again if I want to do this for my other main laptop. All before midnight. Hmm. Anyway, I figure I like reading from the Kindle more than off a computer screen. But the Kindle for PC app does show what all my titles are much much better than the Kindle does, so seeing the book covers in the PC app is very useful.
I'm wondering if I will have this if I reinstall Windows! I plan to do that soon. Maybe I can copy the app and subdirectories and restore that, maybe not. Oddly, the installation was very unorthodox. It did not have me choose an installation location. It defaulted to something somewhere but I don't know where. Looking:
C:\Users\<myname>\AppData\Local\Amazon\Kindle
C:\Users\<myname>\OneDrive\Documents\My Kindle Content
My Kindle Content has 145 folders containing 460MB
Each of those folders has 4-5 files in it.