Majority of people utilizing account 3 will be B40 and M40. As you can see the chart the T20 is holding 82% of the EPF money, and these group are the least likely to withdraw.

Furthermore Account 1 allocation has increase from 70% to 75% of contribution. So increase of 5% from account 1 gives epf more long term secure cash to cover the unpredictability of the account 3 which is most likely will be used by 18% of their total funds anyway.

If it's coming from new contribution, my short answer will be not be affected.

The reason is that any withdrawal will not be coming from existing investment where it will affect the return (EPF need to sell to fund the withdrawal).