We're all saying the same thing; the difference is in whether you're referring to finished or unfinished sizes.
The thing to remember is that your block size is reduced by .5 inch (height and width) when you turn a 9-patch into a D9P. This is true whether you're referring to finished sizes or unfinished sizes, as long as you're consistent.
If you start with 5" finished patches, that's a 15" finished 9-patch, and you get a 14.5" finished D9P.
If you start with 5" unfinished patches, that's a 14" unfinished 9-patch and a 13.5" unfinished D9P.