The 3% comes from the prospectus of the fund - https://(secure.fundsupermart.com/fsm/admin/buy/factsheet/factsheetOCSGFI.pdf) - this is the front-end charge from the fund itself, and the highest I've seen is 5% depending on fund house and asset type.
What this means is 3% from your initial amount will be paid to the fund manager and the remaining 97% will be used to buy units from the fund. Hence for an initial investment of $20,000, you'd need to pay 20,000 + 0.44% x 20,000 = 1.0044 x 20,000 and the value you get is (100% - 3%) x 20,000 = 0.97 x 20,000.
Hence to breakeven (I'm ignoring opportunity costs here and I'm fine to do so because the additional income from the invest bonus from the OCBC 360 account for 12 months needs to be included if I want to be even stricter. Plus, I don't want to go through the additional math involved to account for the TVM), would be 1.0044 x 20,000 / (0.97 x 20,000) - 1 = 3.55%.
And yes I'm aware of the (duration) risks involved - mentioned in my posts that the SG interest rates (IR) must have fallen by quite a bit for the NAV to increase by so much over such a short holding period.