Hi, recently I recorded a singer playing guitar and dragged the whole song to time ruler for ARA tempo extraction. Despite it did a good job, the tempo is half of what it should be. In other words, the metronome seems to be marking 4/2 instead of 4/4 (the current time signature). 
However if I set time signature to 8/8 metronome will mark tempo fine, but I'd like it to be in 4/4.

Is there a way I could keep the tempo map and make metronome mark as written above?
Thanks!