There is a wear in period and DeSmet's paper on BHR vs C+ has some good info about it. I sort of wonder if you do have slightly elevated levels (maybe 3 to 7 ug/L), but not above the 7 ug/L (often referered to as the "safe level"). What would you do? Would you then be concerned and sort of worry about it for awhile? Maybe you'd look at the supplements you've been taking to see if Cr is in them, maybe you'd start wearing a respirator when you're grinding chromoly tubing on your next bike build?, maybe you'd reconsider applying for that job at the chromite mine ... I'm being a little over the top, but the point I'm getting at is that by getting the data, you may create concern that isn't necessary. That's probabaly why Gross suggests getting the test after the wear in period, so that you'll have a more stable and longer term-representative measurement.
Also, before the recent FDA request for more data, the FDA was recommending against metals testing unless there were other symptoms, much like what McMinn has recommended, and maybe that's why the UK follows that plan.