A footnote in the data file explained (citation):

Seasonal adjustment factors have been recalculated to better reflect current economic trends, and the entire series has been revised. New factors will be calculated annually.

Revisions are conducted annually in July, using the U.S. Census Bureau's X-13 ARIMA program.

The series reside in the historical catalog (United States » Cyclical Indicators » Regional Federal Reserve Bank Surveys » Richmond » Manufacturer survey) and include, for example:

• XD5NOCDIF.IUSA = New Orders: Current vs. Previous month - Diffusion Index, (%, NSA)
• D5DT6DIF.IUSA  = Supplier Delivery Time: Current vs. Six Months Ahead, (%, SA)
• D5PMF%.IUSA    = Percent change in raw materials prices: 6 months ahead, (%, SAAR)

Because catalog locations are subject to change, the upper-right search box on DataBuffet.com provides a "find in catalog" mode that accepts a mnemonic.