I just picked up the OEM mudguards and was surprised that they have a big pocket at the bottom of the guards for collecting dirt, debris, mud, stones etc... Is this how they are or am I missing something? I feel they should be smooth all the way down like other mudguards so they shed off debris and not collect it! This is the most bizarre design for a mudguard I have seen and makes no sense. Are the other less expensive mudguards sold on prius chat like normal guards? Any feed back appreciated.