Investors & landlords

Geez.  In going back to look for my last 8606, it looks like that was in 1998 when I rolled over some funds to a Roth (and paid the taxes) and kept another portion in a traditional IRA.  I believe (but don't remember for sure) that there were two separate traditional IRA accounts at the time, one rolled over to a Roth and one kept as a traditional.  That said, it looks like I messed up the math on Part I that figured my basis in my traditional IRA.  The upshot is that the basis in Part I of the 1998 8606 is $4,953 and it should have been $12,180.  Should I just try and update the 2019 IRA worksheet with the incorrect number that is actually on the 1998 8606 form, or update the 2019 IRA worksheet with the correct math that should have been on the form??  I am inclined to do the second and hope there is not a problem in the future.  Or should I just keep the lower number that is consistent with the last 8606 form and figure that given the relatively small amounts, that it won't make much difference?  Thoughts?