You will need to dump more money at 65 as compared to what you dump at 55.
IE. If A dumps in 300k at 55, and B dumps in 200k at 55. B will need to dump in 100k (+4%pa compounding for 10 yrs) at 65 in order to roughly match A's CPF life payouts.
However, if A dumps in ERS at 55, and tops-up RA every year to ERS, then B will never be able to match A's payouts. B can match the capital (which is ERS at 65), but he would have lost out on the interest earned by the capital.
Summary: Your way works if you don't really intend to max out CPF life (ie. ERS and top-up to ERS every year.)
In fact, you can consider FRS and top-up FRS every year if that is enough for you, as that way would also allow you to get Tax Relief (for self, spouse, or children) for the annual top-up every year.