CPF Voluntary Contribution

Can i still make voluntary contributions to my three CPF accounts after my SA hits FRS?

​

After my CPF SA account has reached FRS, do voluntary contributions into all three accounts still go into my SA account? or does the voluntary contributions originally for SA go into OA after my SA hits FRS?

Then for Medisave, after Medisave account has reached BHS, do my contributions from my job income still go into MA? or does it go into SA/OA depending on whether I have hit FRS?