That applies to all non-spouse beneficiaries who are subject to annual RMDs regardless of the year of the decedent's death.
The reduce-by-one language is present in every version of Pub 590-B and Pub 590 before that all the way back to the original Pub 590 for 1994. Apparently prior to 2001 you were able to elect to refigure the life expectancy every year, but that language disappeared from Pub 590 in 2001. I suspect that that change was the result of the Economic Growth and Tax Relief Reconciliation Act of 2001, but I'm not sure. The language has been essentially the same ever since.
