Multiemployer Partial Termination occurred in 2020. Facts & circumstances - Plan is > 100% funded (no With Liab or "to the extent funded" issues). Single large employer who was the only one in the region of the country, shutdown. Plan's permanent break is 5-years. Must plan vest back to 2015? Hyperbole - participant earned 501 hours (1/2 credit) in 2015 and quit. Must plan protect and vest his accrued benefit for the 1/2 year of service ?