PowerPress does not use the MEJS player for mobile devices for a reason. We've found that the native HTML5 player works much better across all mobile devices, where-as the MEJS (JavaScript interfaced HJTML5 player) does not always work on some mobile devices.
Our goal with PowerPress is to provide 100% functionality across all devices and native HTML5 does just that.
The next major release of PowerPress will provide an option to use the MEJS player for mobile as well, with a warning explaining the above. None of the other player options in PowerPress will have this option since they are flash based.