For my HSC I got into B Ec UNSW first round. Then I got a late round offer for B Com USYD. I still went to UNSW. I think it's that good. But I am biased. Plus I was always going to do an economics major.
Your second major can be in whatever you want. And you might even like a major in economics. Everyone talks about it being restricted to try and downgrade the degree. It is exactly the same degree, except for the fact that you have to do a major in an economics area (so yeah that is a restriction). But people are being silly about it. Most commerce students don't use their second major. If you want to do accounting, and go on to work as an accounting. Why do you care that your other major is economics? Same with Marketing, HR, International Business, Finance, etc So it's not that big a deal, and it's a means to an end, i.e. getting to do what you want to do at the uni you wanted to go to.
However, I then transfered after a session to B Com/ B Ec at UNSW as it was a new program that started the year after I did. Technicaly that was just a transfer to a B Com and I selected the Com/Ec stream. You could probably transfer to a B Com after a year with an average of 60 in your first year subjects.
Macquarie is still a good course. Whatever you choose will be fine in the end.