I recently tested students with the new Life and Work CASAS for the first time. Students expressed that they found the test more challenging, however, I did not see a drop in scores or levels and achieved as many level increases as before. Try testing students with the same level test that they previously took in CASAS Lifeskills to start with. Example: Level 35 = Level 185, Level 36 = Level 186.
Students were comfortable with the change and there didn't seem to be much of an adjustment period. I don't teach CASAS concept skills to students primarily because I see results from daily projects, so I don't know about an adjustment period for the change of content.
I would be interested in hearing what kind of results you see and if there is a significant difference.