The BBA and BA-Psych are two separate degrees. What happens is, you do the BA-P degree, where you'd usually have a whole heap of electives (see the handbook...). But, instead of picking and choosing which electives you want, you do all business units.
Because I'm doing BA-Psych, I'm majoring in Psych. If you did a BA-Media, you're majoring in media. Yeah?
BUT, in BBA, you've got a choice of
'modules'. This is where you choose a general area you want to study. In your case you might choose Accounting (I chose finance, and want to do biz law too, but we'll see how that goes). Regardless of what you choose, there are certain 'core' units which you HAVE to do, and they span across all the domains of business... so you'll have to do finance units, have to do economics, have to do acounting, etc.
That's really all the choice you've got in this degree - which BBA module you do. Later on, in like 3rd year you get to choose 2 psych units, but that's not a major or anything special in the eyes of the uni, just two units you decided to do.
Click
here and you'll get an excerpt out of the MQ handbook. Find the BBA+BA-Psych (page 8) and this might all make some more sense... Note the level 1 modules you can choose from(and then continue with level 2 modules of the same topic), note the "8 cp [credit points/2 units] from PSY"....
You'll have to excuse me I've been talking to customers all of today. I hope I make more sense at work!