I'm not 100% certain how it all works Snowy....i.e. how much you get back for every u/s, but from what I can tell, they charge different amounts depending upon what stage you are at, for example the nuchal fold scan is a different cost to that of the 18 - 20w scan (this has been the case with me). You always get a rebate as Jessica pointed out though. And yes, the nuchal fold scan is covered by Medicare.