Differences in CS3 and CS4? Eye one and targets

I’ve encountered an interesting situation in how CS3 and CS4 handle color. I printed the test charts from within each version of photoshop, all settings being equal. Relative colormetric, same paper settings. and the profiles I’m getting are substantially different. Is there a change in the way that PS handles color that would cause a substantial difference from CS3 to CS4? I’m a little cinfused, as I would imagine that if all settings remained the same, the output (and profile) would be much more similar than they are.

(I can send copies of the .icc if that might shed some light)

Thanks in advance

Jeff