For 1972, I see the following:
Series 1 1 to 132
Series 2 133 to 263, plus check 2 again
Series 3 264 to 394, plus check 3 again
Series 4 395 to 525, plus check 4 again
Series 5 526 to 656, plus check 5 again
Series 6 657 to 787, plus check 6 again.
So, check 1 would have been printed 2x on the series 1 sheet, while series 2 through 6 would been 4 ea. (double printed - 2 each on the previous series sheet and 2 on the actual series sheet).
http://https://drive.google.com/file...ew?usp=sharing