I work in a field where we are negotiating over price daily. We often are using "weird" numbers because we know it will push our price just over a competitors, and because the sellers will find our number psychologically "interesting" over those competitors. We also make sure our escalation numbers are not "normal" for the same basic reasons. It has worked well for me, though I'm not sure it would make as much of a difference if my competitors were the kind of people who read articles on hbs.edu.