We do the same for initial verification and weekly ports. Are you recapturing the FB and BH reference image after shifting on films? When taking orthogs (on lateral) are you looking at spine and sternum to make sure they both are on? If not, you may need to have to patient take in air or let some out. We also try to get the patient to hold their breath exactly in the middle of the coaching bar. Same is true on FB setup (green is not good enough for us…we get those FB translations as tight as we possibly can especially for yaw, pitch and roll.) When we take the extra second or two to do this they usually fall right into the threshold when taking in breath for their BH image.