Check with the doc that is going to do your AN surgery. He will have you tested to see if a BAHA is a good match for you. Following the test, and if you qualify as a good candidate, he may be willing to put the abutment in your skull while you are having surgery for your AN.
That is the way I had mine done. Three months later I was listening through my BAHA. I chose Cochlear because they have two BAHAs. One is more powerful than the other...I am about to get the more powerful one because my good ear is not so good anymore. Cochlear also makes cochlear implants, and I have already talked to a doctor abut getting one of those when my good ear really quits.
You can use a BAHA attached to a head band for a test but that is no comparison to having one that is attached to your skull. I really enjoy my BAHA. I am not familiar with the Oticon, but I know posters here enjoy Oticon BAHAs. I think it is a Ford/Chevy comparison, but try them both and you may like the controls of one over the other, or they may sound different to you, but again, what you hear in a headband test is far different from what you will really hear.
Get it approved with your insurance. Hope this has helped.