Successfully used both my elite vouchers for a flight after the membership year ends. J4+ was indicated on business class.

The onward leg is a 5 hour connection which only needed 1 voucher.
The return leg was a 37 hour stopover and needed 2 vouchers, opted to use it on the longer leg.

Was advised that I needed 3 vouchers for my flight because the return flight was a stopover in Istanbul and not a connection.