After PER, your file is sent to your VO from where the processing start, (Back ground checks on documents etc), just make sure if you have given your ex. experience then it can be verified. I suggest you meeting your ex. boss to lighten up the matter
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Informing VO will be best thing through CSE after PER. It won't hurt your case but will further strengthen it incase if your ex . company tries to delay things!, in that case VO will know what to do (might take alternative step in a positive way)
Others can give opinion too with experience of same situation.