If you go to page 299 of PMBOK 4th edition you will see a decision tree diagram which uses EMV (Expected Monetary Value). In that diagram they chose higher EMV as correct answer over lower EMV.

Now if you open Rita 7th edition and go to page 388 you will see decision tree diagram example. And here Rita is choosing lower EMV as correct answer over high EMV. There is another diagram on same page and Rita again choses lower EMV and not higher EMV.