Olivetti Age Confusion

The old typewriter database, www.tw-db.com indicated that my Olivetti Lettera 22 was made in 1954. However, the current typewriter database, www.typewriterdatabase.com  which is cross-referenced with many different National Office Machine Dealers Association (NOMDA) serial number guides, indicates that my Olivetti was, in fact, made in 1957. This means that The Typewriter Clinic was not the dealer that most likely sold my Olivetti.--The dealer listed in the 1957 Seattle Telephone Directory is the Printing Calculator Company, which was located at 923 Western Avenue. In 1956, this was the location of Olivetti's offices. I believe that the Printing Calculator Company was tied in to Olivetti, because at that time, Olivetti's most-advertised products were from their adding machine line. However, this is not to say that The Typewriter Clinic could not have sold my Olivetti--they still sold Olivettis in the early 1960s. By 1958, they specialized in Adler typewriters. However, there are some duplicates on the Typewriter Database:

up to 904000	1950				13,24
935000	1951				13,24
981223	1952				13,24
999999	1953				24
116999	1954				24
213320	1955				24
312518	1956				24
ALTERNATE and possibly erroneous data for 1954-1956 from OMEF between these lines
up to 626232	1954			Obviously, new serial numbers	6,29,30
626233	1955				6,29,30
636601	1956				6,29,30
ALTERNATE and possibly erroneous data for 1954-1956 from OMEF between these lines

This means that my Olivetti could have been made in 1950, 1954, or 1957. After seeing type samples of a 1957 Olivetti, I think that my Olivetti may be from 1950. If this is the case, it is a remarkably early Lettera 22. It matches one at the Metropolitan Museum of Modern Art perfectly. MoMA says that their Lettera 22 was made in 1950. http://www.moma.org/collection/object.php?object_id=2967. I will post their Lettera 22's serial number when I am able.