Thanks, Paul... that does help. Oddly, I didn't need to change "contrast" before. What I find, comparing the Viewer results with ACR results, is that ACR is still showing a bit of overexposure - nothing that can't be dealt with easily, but still a bit different from Viewer. I remember people - I think a Shutterbug writer was one of them - explaining that ACR uses a few more heuristics to speed things up, and others telling me that Adobe might not have complete access to the raw code. Anyway, the differences seem to be minor now.
As for CS5, fortunately that version can download the latest ACR.
W Alex Stewart