So explain a bit better what you have, although correct, but you have master die doubling.
A very high percentage of the 1972 cents had a master die that was created by a normal master hub with doubling on it. So check this list to show how many dies this could affect:
Note on this chart how many master dies were created? Two. So if one is was normal and one was doubled, how many dies would be affected? Half of the coins used from that year for all three mints. So this master die doubling if all the working hubs and working dies were used. 50%. Making this type of master die doubling common. Hope this helps. (Sorry the teacher in me took over)