Vendor came out on 3/2017 to inspect dry chemical extinguishers. 67 extinguishers were dated 2005 on the label. Replaced 31 with new. Performed an annual inspection on 36. Didn't think that was allowed per NFPA 10. He stated as the manufacture date was August of 2005(got this info from the manufacturer), this was allowed. Stated hydrotest not needed until then. Oddly he back dated the inspection tags to 12/2016 on the inspected cans and 3/2017 on the new.
It appears this was an attempt to avoid the 12 year hydro test.
The cans had refill labels dated 12/2011.