What is the most amount of ptptn discount given over the years?

If got balance rm20k, can pay half in lump sum to get discount? I.e. pay rm10k first for x% discount.

I have some questions:

1. If I open account for my child, do I choose "anak kandung" and do I name myself as the beneficiary?

2. If I put in RM1,000 today, can I withdraw the money freely? Is there lock-in period? Do I need to submit any application, bring birth cert etc?

3. Is withdrawal done online, at PTPTN counter, or at any bank counter?

4. Is there any minimum balance requirement? Can fully withdraw all RM1,000 but not close the account?