Refer to E.4.3 Sites Not Defined by ASCE 7 Methods.
In this case Sp ( peak ground acceleration ) will be agR For TNCR =475 years . However , the figures agR For TNCR 475 years = 0.05 G and For TNCR 2500 years =0.32 G are not consistent. If 0.32 G is correct , TNCR 475 years should be 0.32*0.66 G =0.21 G.