Not many people are aware of this, but there is an electronic sensor inside Powermates that detects the presence of competitor's eyepiece and triggers passage of electrical microcurrent through a liquid crystal layer sandwiched between the upper two elements, effectively turning it into an extra refracting lens element, which was specifically designed to make it impossible to obtain clear focus.
Seriously, it sounds like you are pushing the power too high. Try with the 24mm. Like John says it will be a very warm image by comparison with the XW-10. My TV barlow warms the image through any EP, and I find the combo of TV barlows with TV EPs extra warm.