$17/$50 is roughly the 35% royalty rate. KDP offers both a 35% and a 70% (less delivery at about $0.15/mb in rounded kb increments) royalty rate[1]; however, the 70% royalty rate is only available in about 14 countries and you fall back to the 35% royalty rate elsewise.

[1] https://kdp.amazon.com/self-publishing/help?topicId=A29FL26O...

[2] https://kdp.amazon.com/self-publishing/help?topicId=A30F3VI2...