Harlan Grove wrote...
....
. . . If it should return #N/A, then perhaps it should resemble

=IF(C16<B5,B5,INDEX(B5:B13,MATCH(C16,B5:B13)+1) )

So maybe I should have made it return #N/A.

=IF(C16<B5,B5,IF(C16=B13,#N/A,INDEX(B5:B13,MATCH(C16,B5:B12)+1)))