[p1acebo]

Is it better to start payout at 70 instead of 65?

Definitely not.  See below extracted from a website

Well, we will need to look at the numbers to decide. Assuming you are now 55 and have the FRS of $186k in your CPF, the payout at 65 will be $1,500/month (Standard Plan). The payout at age 70 will be $2,000, quite a bit more! Now let's do some simple analysis. For $500 more a month, it is worthwhile to defer the payout for another 5 years? That's the total loss of $1,500*12months*5years = $90,000 immediately to start. With an additional $500, it will take 15 years to break even, meaning, you will need to live to age 85 just to breakeven. You decide if this is worth it.