for adding ob numbers to ba bookings, if you load up mmb, then do the workaround to get the older interface you can still add it in there https://www.flyertalk.com/forum/35819222-post16.html

so on chrome load up the booking on mmb, do More tool>Developer tools>scroll down to the MMBVERSION field>change it from OPT-IN to OPT-OUT>close developer tools tab>refresh MMB