POH Limitations for that P210N prohibits flight into know icing even though it was factory equipped with a known ice option. Same situation as most the Cirrus SR22s.
91.9 Civil aircraft flight manual, marking, and placard requirements.
(a) Except as provided in paragraph (d) of this section, no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.