HSN currently has (both with 1 year of service)
Rebel 2 with 1200 min for $60 and
Luna Pro with 1500 min for $80 (Today’s special 2)
Some phones now only come with 6 months of service. 
Question for tracfancier:
Thanks for your answer above - I know what I wanted to do (swapping service dates on two phones) is complicated and giving up on that.
My next best move is to buy the Luna Pro, transfer my service on the line that currently has 400min / 1000 text / 600MB left (which is on BYOP SIM and expires early Jan 2018) to it and let the system add the 1500 min / text / data to it for another year of service.
Can that be done?