Yeah, no.
When the measures were improved back in 1994, what had been the U5 measure was renamed the U3.
http://www.bls.gov/mlr/1995/10/art3full.pdf
The pre-1994 U5 is the post-1994 U3. It's a name change, not a methodological one (for that particular measure; the others were adjusted more concretely).
Paywalled. Though even going by the title of the story alone, it's still not what zenkai was claiming.