yeah, use ATM - cash out OR transfer to your BI's account.
then online U can move to other bank - safer than cash out and walking around

Thanks & credit go MasterConfucion as he pointed me to the new ATM-cash out options in PTPTN's SSPN page 

USJ Branch is open 7 days / week.
I use BigPay to deposit into SSPN. They slot in the card, you key in your pin, done.

Yes

1) Yes.

2) No.

3) Around 2-3 working days.

In this case from the wording I think don't need 12k. Coz your 2020 is -6k deposit, but you claim 0k tax deduction. Don't think negative carries forward.
Total claimable = Total in - Total out in that year itself.

No, if you skipped a year, you start from fresh again so just 8K is required for 2021.

already told by MUM.....

I don't really concur.

Based on your earlier example, it means for year
2019: claim 8k tax deduction
2020: no claim
2021: claim 8k tax deduction
2022: no claim

Yes it saves the hassle of in and out. But those years you don't claim you lose out a lot in additional taxes already. Like I said unless you're borrowing from loan shark, or can't afford to have 8k savings a year, I think it's just better to leave the money in there, earn 4% and save on tax.

If you're at 14% marginal tax bracket, that's a RM1,120 savings
If you're at 21% marginal tax bracket, that's a RM1,680 savings
If you're at 24% marginal tax bracket, that's a RM1,920 savings

Also, I think at the moment the tax relief is only until 2020 (though it can be extended in future Budget), so it won't compound 8k,16k, 24k, 32k, etc.

Per child? 
if have more childs can seek to pay lesser tax?

if only got 1 child that the husband already seek for tax relief, then wife cannot seek for tax relief?

so 1 child can only be opened under either father's name or mother's name?
if father had already opened for that child, the mother cannot open again under her name for the same child?

if both can open, then only 1 can claim for tax relief?

if wanna be entitled for interest in 2019, deposit must be done before 15th Dec 2019

the same applies for every year

check page 97, from post 1921 by forummer Rapple?
then follow the replies/comments/question by others ...