28.8 is not even that for Optus.
I joined up to Optus ADSL last month, and my starter account was a base 300MB limit. Needless to say, I got through that pretty fast, and was down to '28.8kps'. But sites were loading as if they were around 10kps or less all the time, and I can back this observation up with fact because when I was on dialup, sometimes I would connect at around 28kps (bad connection), and it would be way faster than the so-called '28.8kps' Optus blasts you down to after your limit.