dba_tab_modification timestamp mismatch for last insert on table in oracle 12.2.0.1.0

Hi ,

Am in a process of doing PITR of specific table from particular PDB, it's preplanned activity so  i have taken the exact timestamp before erroneous insert on table and then did insert.

when i checked the timestamp of insert on particular table from the view dba_tab_modifications both timestamp are mismatching around 15m. PFB.

i feel It would be practical if we get the timestamp of the erroneous update after the fact rather than planning for it. What if timestamp is not noted before erroneous update, you know most of times that will be the scenario, so i want to figure out a way to identify the timestamp as when erroneous updates happened.