6th series Topps Sp's 1961-63

[BillP]

I've been trying to figure something out for a while. In the beckett guide there is listed sp next to selected cards in the 5th series of 1961 and the 6th series of 1963. Also 1 card, 476 perez in 1967. So here's my question: If the size of the series is a standard 77 and there 's 11 cards per row, doesn't it stand to reason that there are more sp's that want is listed?
Let's take 1963 as an example: There are 5 cards listed as SP in the 6th series. 500 killebrew, 485 long are 2and from the bidding prices 496 (rookies) has to be a short print even though it's not listed. So has anyone seen a 6th series uncut sheet.
My point here is that I think that in the 60's, maybe up until 68, there was uneven production numbers within series.
Again take card 476 perez in 67. How does only 1 card get sp'd ? Only thing I can come with is that there are 2 sheets A and B and the perez in this case was pulled in favor of an added checklist? don't know.
Feedback welcome. Thx BillP