what talking you?
i tried on my s8+ and it works. you mean your A5 is newer than my S8+?
Nothing to do with bootloader version and there is nothing to do with the firmware version on sammobile. if you are using a non local set, the CSC file will not just replace itself automatically when you flash. even if it does, there will still be an issue.
The thing is if you wish to switch out csc, to change the status of indo local set to sg local set, you need the help of service centre which they will do magic. But i doubt you are able to gain support for your non local set in sg though.
Previously when we tried to load S7 series with european firmware which changes the csc code, only the service centre can change back the code with a downgrade of OS when at the time nougat wasn't available in sg yet...