[M.D. Holloway]

It is not uncommon for OEMs to change or update MRO products and keep the older version around for use on older equipment - the service manual may call out for it specifically. The odds that these greases are fundementally different in performance is pretty remote.

The greases are different in respect of color and consistancy and maybe even chemistry. There are some greases that are not supposed to be made or even used in the states (Barium based) and certain addtives can't be used without serious warnings (Antimony). Regulations maybe a reason for the change as well.