Why is there discrepancy between Educ codes and data for 1970s CPS?
We are not aware of any discrepancies between the EDUC codes and the data for any years in IPUMS-CPS. I took a look at your extract, and since it was limited to respondents ages 16-70, the frequencies for each year will be different than those on the codes page for EDUC. If this does not solve your problem, please provide more detail about what type of discrepancy you are seeing.
Hope this helps.