Question: What happened to film speeds of black-and-white negative film?

Is "This revision also saw significant changes in the definition of film speeds in order to accommodate then-recent changes in the American ASA PH2.5-1960 standard, so that film speeds of black-and-white negative film effectively would become doubled, that is, a film previously marked as "18 DIN" would now be labeled as "21 DIN" without emulsion changes." the correct answer?
Choices:
(a). yes;
(b). no;
(a).