UR242. different sound between direct monitor and playback

I have a steinberg ur242 and cubasis app v 1.9.7 and ipad air 2 and dspmixfx.
I adjust the fader volumes of dspmixfx master out and 3,4 channels and track cubasis and master volume on 0 level .
I connect my guitar multi effect pedal to the input lines 3,4 ( back side of ur 242 ) for stereo recording and i do recording but when i play back the recorded track ,the sound volume is lower than the when i was heard through direct monitor of ur 242.
I mean that sound power and quality of direct monitor sound card different with playback of recorded the same sound.
Please help me .