Nero says its a 702MB medium (overburning problem)

I have a LITE-ON LTR-48246 CD writer. I can’t get it to overburn a CD.
Here’s the deal:

I’m using Nero 6.3.1.25 Demo, I have a full 5.x version too. (couple of months ago i burned 800MB disc with nero5)
I have set the “Enable overburn Disc-at-once burning” to 100 min
when I try to burn data on a 900 MB CD-R medium it sez its a 702 MB one. It also says 702MB when I put the 800MB CD-R in.
The thing is, I ran this test and it said the medium is 900MB

What should I do?

Do you burn at DISC AT ONCE mode? I think overburning is only enabled in this protocol

Nero will tell you that the media is only 702Mb, this is normal, just proceed to burn, and with media like that, better burn it slow. I always used 4x, even then c2 errors were huge.