first of all how do you measure power. I hope with a PEP meter. Normal meters should show only 25W and this is perfectly normal.
second not sure if you understand digital audio. If you have 16 bits available it is MADNESS to use the upper bits only. In order not to get any distortion at the DAC side at the receiver you should NEVER put more than -12 dBFS into the adc. If you go up to 0dBFS your DAC will never be able to recreate distortion free signals, even worse with processed audio.
So if you can see the ADC input (Thetis has this function, or else you can use external software like the Orban sound level meter free app, you should set your microphone for this level, so not 0 dB !!! In that case you are already 12 dB too high.
The Motu is a 24 bit device so why be an idiot and only use the two MSB if you have 22 unused ones ????
Stop thinking end of scale.