I think these two tests have wrong results. According to CSL-1.0.1, which introduces cite grouping, all cited items belong to the same cite group and so the delimeter between citations should either be the value of the "cite-group-delimiter" option or ", " (and not the delimeter set in the cs:layout element).
So the results should be:
Smith 2000a–e, 2001 Smith 2000a;c–e, 2001
Smith 2000a–e;2001 Smith 2000a;c–e;2001
To get these results you should set the "cite-group-delimiter" option to ";":