But while some developers see profit in these location mutations, they are giving headaches to other groups, such as taxi drivers and mailmen.

George Dourif, spokesman for the Metropolitan Taxi Board of Trade, said ''a lot of developments have gone up lately that the real estate people want to put classy addresses on, and this has become an increasing problem for our drivers.''

Steven Brauch, the head of the Taxi Driver Institute at La Guardia Community College, in Long Island City, agreed. ''We're aware of an increasing number of these vanity addresses,'' he said, ''and its a problem they have to deal with - as well as the English language and how to find north, south, east and west.''

Such permutations were viewed more seriously, however, by John M. Nolan, who as postmaster of the New York City Division of the United States Postal Service is responsible for mail delivery in Manhattan and the Bronx. ''These changes have been going on for a long time,'' said Mr. Nolan, ''and are becoming a big problem for us because they lead to misunderstanding and duplication.''

He said location mutation both slowed down mail delivery and drove up costs for the Postal Service, and thus ultimately the public.

MR. NOLAN said he considered the worst offender to be the complex of 14 buildings in the Madison Square Garden area that now have ''Penn Plaza'' addresses. He noted that addresses such as 11 Penn Plaza and 12 Penn Plaza were completely out of sequence - indeed that the former was really the Montgomery Ward Building at 393 Seventh Avenue while the latter was the Bowery Savings Bank at 470 Eighth Avenue.

''If Madison Square Garden comes down, we want to redesignate all the buildings now called 'Penn Plaza Something' with a two- or three-digit numbered address,'' he said.