If you use the Kindle Countdown Deal, it's my understanding that you receive the 70% royalty even at the discounted prices. Here's where I found the info: https://kdp.amazon.com/help?topicId=A...
My book The Watchman's File is now being featured in its second countdown sale..and I find it's by far brought be the best results in terms of copies sold. frustrating having to wait one month between sales. I'm also promoing those deals by buying adds on other sites like Book Gorilla and Kindle Deals..which I think helps. But looking for other such paid for promos that can give a big bang for buck for mysteries...
I tried a Countdown promotion over the holidays. There was a modest boost in sales during the promo (about 3x my average weekly sales). However, after the promo was done, sales dropped lower than before, so there was no lasting effect.
If so, has anyone had experience with it yet?