Male BPs do go for more then females, you just aren't examining the correct price ranges and timing. Once a morph drops below 1k a lot of its investment value drops with it. People try to buy powerhouse males. People who have 5k to spend on a project aren't going to purchase low end males and high end females.
I guess what I'm trying to get at is.... Males as a gender are sold for more almost always but males of a particular morph when compared to their female counterpart may or may not be priced higher depending on the current state of the market.