This  is  a simple song.  I've played it a hundred times  in  front  of many people
and hung out with the  band backstage twice on their tour.

Regular  E tuning

for the verses
A and D

for the Pre-chorus
C-Bb-A
A-B-C

For the Chorus (Bar Chords-Heavy Distortion)
A and D

If you listen to the song you will find  out in the chorus the part where
he bends B into A.