This is from Dork32 example
"case 4 contribute then withdraw
1 jan opening balance 10k
10 jan receive 1k into account. total balance 11k
20 jan withdraw 1k. total balance 10k
31 jan closing balance 10k
withdrawal and deposit receive no interest received no interest. so interest only on 9k so lowest balance is wrong."
And below is illustration from CPF:
Illustration 2 – Deduction transaction occurs after contribution transaction
Amount
Month Beginning Balance $2,000.00
Contribution $500.00
Deduction $50.00____
Month Ending Balance $2,450.00
In illustration 2, the eligible monthly balance used to compute interest is $2,000.00.
As the deduction of $50 occurred after the $500 contribution was credited to the account, this deduction did not impact the eligible monthly balance used for interest computation, and thus, interest is computed based on $2,000.00.
My comment:
Just compare the 2 above. It is obvious that dork32 was wrong to say that interest would be paid on only 9k in his Case 4 example. The correct figure is 10k which is the LOWEST BALANCE in the month