Really weird find...Again

OK, a couple months back I posted that I had got some rolls to search and found 3 CWR that, when opened were B.U. 1974 (P) pennies.
So, today my wife and son were going to the bank, my son was getting $5 in pennies, so I ponied up what I had - $10. My son comes in the door very excited and pulls out 14 CWRs, all in very old paper rolls, with "1974 P BU" written on them. Of course we opened them and sure enough, inside is 1974 cents in pristine condition. We split the rolls fairly.
Now, what is it with 1974 BU pennies? Just my area perhaps.
Anyhow, good find. We are happy!
So, today my wife and son were going to the bank, my son was getting $5 in pennies, so I ponied up what I had - $10. My son comes in the door very excited and pulls out 14 CWRs, all in very old paper rolls, with "1974 P BU" written on them. Of course we opened them and sure enough, inside is 1974 cents in pristine condition. We split the rolls fairly.
Now, what is it with 1974 BU pennies? Just my area perhaps.
Anyhow, good find. We are happy!