I've played with this a bit more, and it seems to be pretty similar to last time - good on some Penguin/Random House books (including at least some subsidiary imprints), only if the "list price" is over $9.99 or over. However if a title with a list price of $9.99 or over is temporarily on sale, it will deduct the $5 from the sale price, even if that is less than $9.99. And if the sale price is less than $5, it will cover the whole price, and says it will keep the bit left over to apply to another title. I haven't been able to verify that part yet this time, but that's how it worked for me last time.
Here is an example from today:
Self-Defense is the 9th in the Alex Delaware series by Jonathan Kellerman. It has dropped to $2.99 at Kindle US, and as a Ballantine Books/Random House imprint seems to be eligible for the credit, since it's normally priced at $9.99. So it showed as free after credit on its webpage, and when I bought it, that's how it turned out.
If you want to buy
Self-Defense, links and more info are in this post in the mystery thread:
https://www.mobileread.com/forums/sh....php?p=3881821
I also found a PRH title that was on sale for $7.99 and the web page indicated that it was going to deduct the $5 from the $7.99 and let me buy it for $2.99, but I didn't want that title, I was just testing things out. And now I can't remember which one it was, so I can't pass that along. Sorry...I've been looking at a lot of PRH books!