Is the LUNCHSUB variable in the CPS ASEC really only asked to households below a certain income threshold?

There is no evidence that this is the case in the codebooks, nor in the actual data (which show that households with incomes well above poverty thresholds report having school-aged children who receive free and reduced-priced lunches). The description here thus seems inaccurate (and outdated because the eligibility thresholds are 130 and 185 percent of the poverty level for free and reduced-priced lunch, respectively, not 125 and 195 percent). Thanks in advance for any guidance with this question.

Yes, I think you are right about this detail. I’ll send a note about this to the IPUMS CPS team and ask them to clarify the documentation. I think the tricky bit here is that the information discussed on the variable description is theoretically correct, however, in practice a small share of households do not comply to the eligibility rule. This generates the observation you point out.