Since August, you can already add subsequent investments to your Sun Life mutual funds through BDO Bills Payment (online and over-the-counter). Please see the published Sun Life guidelines here.
The good thing about this service is, if you're using online bills payment, you can set up a recurring payment to the mutual fund account of your choice. You don't need to enroll to the auto-invest option and be tied to their schedule which is the 5th or the 20th of the month. Terminating the auto-investment is also easier as you don't have to fill out and submit forms. You can just stop the recurring payment.
Comparing this new service with their old way of adding investments (bank transfer to their BDO account then submit a screenshot of the transaction through Sun Link Online), I noticed the earliest period the funds can be transferred to your funds is 1 business day. If you use the old service and make it before the 12 noon cutoff, that day's NAVPS will be applied.
Either way, both facilities are good as it gives us more ways to add investments.
Happy investing!