On the reverse of the US penny, why is the "o" in the UNITED STATES oF AMERICA in lower case?

Many people snapped up the new pennies [in 1959] as "collector's items," particularly following a news story pointing out the small "o" used in "THE UNITED STATES oF AMERICA" as an error at the Mint. This impression was quickly corrected by artist [Frank] Gasparro who said that the small "o" was not done in error but rather had been done deliberately to give design appeal to the lettering on the penny. Citing precedents for the lowercase letter, such as the Franklin Half Dollar, the
Liberty Walking Half Dollar, the Peace Dollar, and several commemoratives, he said, "I did it to break up the pattern."

http://www.archive.org/stream/abrahamlincolnse00unit/abrahamlincolnse00unit_djvu.txt


This will no longer be the "case" as the new Union Shield reverse from 2009 will be used in the future.

https://en.wikipedia.org/wiki/Cent_(United_States_coin)