"If, after 30 days, you haven't chosen and selected Most Helpful opinion per each gender, one will automatically be chosen for you. Neither the Question Asker nor the user awarded Most Helpful will get Xper points for these automatic selections. Automatic MHOs are chosen per gender based on engagement: likes, replies, length, time, xper level, among other criteria. As long as you're giving helpful opinions, we'll find them!"
Of course, it does. MHO% is the ratio of the number of your opinions that are selected as Most Helpful Opinion (not necessarily by the asker), to the total number of your eligible opinions. That's it. I keep an eye on my total number of MHO and they increase when I get automatically selected MHOs and my MHO% is correct with respect to the value of total MHOs.