In that article they talked about how $9.99 was a good price for an e-book but $14.99 was excessive (I greatly summarize here). So my thought was is $9.99 too much for a Kindle version of a book that is selling much better as a PDF on my blog for $11.00?
As an experiment, I just lowered the cost of the Kindle book to see if that will get more interest going. Anyway, let me know your thoughts.
Here are the links to the book.
USA Kindle Site: https://www.amazon.com/dp/B00IPLUJXO
UK Kindle Site: https://www.amazon.co.uk/dp/B00IPLUJXO