Have you ever noticed that most addresses in Oconee County have four digits starting with a "1"? Four digit addresses are only necessary on long roads, but even a short street like Winthrop Place uses them. That street has ten houses numbered 1010 through 1080; the "10" is unnecessary.
But a real problem is revealed with the way the county has allowed buildings to be identified. Ideally, every building should have a street number, but this was not done for the two new office complexes on Daniell's Bridge Road. Instead, one address for each parcel of land was retained, and both building numbers and suite numbers are used. An address out there looks something like "2500 Daniell's Bridge Road, Building 200, Suite 2B." Besides being hard to remember, even the post office has trouble with this. Depending on what order and formatting you use to enter this information into the postal database it returns different ZIP code extensions and delivery points. No wonder I've had mail lost out there!
I would guess that the convention of using three-digit building numbers developed to accommodate ranges of suite numbers precisely so that three sets of numbers don't have to be used in an address. The second suite on the second floor of the second building could be numbered 222, eliminating the need to insert a building number. I've seen a planning ordinance establishing such a scheme for numbering units in apartment complexes with only one street number, but the same ordinance actually required commercial properties to have a different street number for each building. The planning department in Oconee County should get their addressing system cleaned up a little bit.