Thank you for bringing this information to our attention. It looks like there are a few different things happening that explain the large differences from supplement to supplement.
First, it should be noted in 2010 and 2012 Computer and Internet Use questions were only asked at the household level, so all person records within a household are identical (we have some sample notes here).
Second, the differences appear to stem from additional universe requirements that were not previously listed. Our CPS Team has updated the universe tab for CINETHP, which will be live in our next release. The changes to the universe statement are as follows:
Oct 1997: Respondents age 15+ who live in a household that has a computer.
Dec 1998 and Aug 2000: Respondents age 3+ who have a computer at home or who have used a computer at home.
Sep 2001, Oct 2003, Oct 2012, Jul 2013, and Jul 2015: Civilians age 3+.
Jul 2011: Respondents age 3+ who have a desktop, laptop, or tablet at home.
I hope this helps. Again thank you for bringing this to our attention and our apologies for any inconvenience.