I have no idea what’s going on here but when I try to add a permission using Set-Acl on a share where the share itself has inherited permissions, all inherited permissions are removed. Consider the following setup:

Write a powershell with below scenario attaching the file for reference.
I have 16 files same as reference files which contain the information of permission associated with different window screen for profiles.
Window screen are defined with the id that is store in fpAUTKEYS
and each files contains thousands of fpAUTKEYS and associated permissions for each in fpMENUAUT
Each file have fpAUTKEYS which shows the id of the screen and follow by the path in () and have fpMENUAUT which contains the permission.
Each file may have different number of fpAUTKEYS but id is same meaning same fpAUTKEYS can be found in other files with different permissions but same path.
I want to create a file that check all the fpAUTKEYS in all the files if similiar found in x files than set the fpAUTMENUAUT with larget and highest permissions and if only uniqu fpAUTKEY found then saves the result as it is.
And i want to same structure of the file just update the new l fpMENUAUT of the file along with the path