Historical Assignments data entry in HRMS after go live

Hi,

I want to know what would be the impact if i entered the historical assignment data after Go live.

For example; I entered the current data of  employee at the time of go live, i have ran the payroll of the employee and after two three months if i enter the historical data of this employee the application gives me an option for insert and replace. i chose insert for the data entry.

I wanted to know if this would impact any module?

Is this kind of entry is recommended or not?

Or the historical should be entered before the time of go live?