ACA Flag - Update All records or just one record of 01/01/2015

All,

Please help about the ACA Flag. Please correct me if I am wrong in what I understand.

scenario 1 --

if an employee starts in 2014  and have per_all_people_f records as follows

12-dec-2014 to 15-jan-2015
16-jan-2015 to 13-mar-2015
14-mar-2015 ...31-dec-4712

Do I update just the record "12-dec-2014 to 15-jan-2015" with PER_INFORMATION26='Y' or do I have to update
the ACA flag = Y on other records like "16-jan-2015 to 13-mar-2015" and "14-mar-2015 ...31-dec-4712"

Thanks for your help,

Sachin