Option # 1:
You ask for the postponement and hopefully get it without much
delay.
This would involve re-scheduling the trip etc. Some costs occur,
but safer, since you would carrying the PCC you want.
Option # 2:
You go to the interview with the current PCC, hope that they do
not look deeply into that (or) convince the consular officer about
the fact that you have not entered India after the first PCC.
There is a chance that he/she would be convinced and let you go.
If they don't, then you have the problem of making sure that your
current H1B visa remain valid,
Take a trip alone back to US,
Get the PCC and go back.
This looks like a lot of hassle and additional cost, leave and so on.
Take an appropriate decision.
Raju