I added a negative phrase match keyword, why did it turn into a negative exact match keyword?

In one scenario, outlined below, PPC.tools changes the negative keyword match type to work around Amazon’s word-length limitations. Specifically, Amazon enforces a limit of four words per negative phrase match keyword.  If you attempt to add one with more than four words, Amazon will reject this keyword. The limit for exact match words is much longer at 10 words.

In order to maintain your strategy goals in this scenario, PPC.tools converts the negative phrase match keywords that exceed four words into negative exact match keywords.  This ensures these keywords are accepted by Amazon and that you still gain some of the benefits of the negative match keyword.