TH dividends are calculated based on monthly minimum balance. So if you keep 70k in 2014, you will earn xx% of the dividends payable for each month (divided by 12)

If you withdraw 65k in January, the minimum monthly balance would turn into 5k, so you would only earn your dividends based on 5k for that particular month. It doesn't matter if later in that month you add RM100k into the account to make the blance RM105k, because the monthly minimum is already 5k. In February though, the monthly minimum balance is then RM105k, unless you withdraw part of the units in February

Edit: As a muslim, I do recommend my Muslim friends to invest their money in TH and not ASB. TH offers similar fund performance, zakat already paid for, and most importantly, does not have any shares in non-syariah compliant companies like banks. However, do note that I am not issuing any fatwa, I'm just speaking my mind out.