Let me attempt a rough projection on your retirement numbers:

Currently you have combined net worth of $1.32m = $800k + $100k + $420k.
I don't see any other investment other than your home which does not generate passive income.

Assuming your savings can grow at a rate of 5% per year and you work till 60, average of 15 years to go. That would give you another $1.1m. Assuming your home appreciate 2% per year (if the cooling measures are not removed) it's value grow to $1.6m. Total net worth at 60 = $2.9m (= $1.1m + $100k + $420k + $1.6m -$300k)

Out of the $2.9m, I think by then (in 15 years time) the minimum sum the CPF requires will $300k each, or $600k to be set aside for both of you. Combined medisave to be set aside will also probably grow to $300k. The situation could like that in 15 years time:

Combined minimum sum in CPF = $600k
Combined medisave in CPF = $300k

Property value = $1.6m

Cash & CPF available = $400k.

As you can see, your available cash/CPF money that you can use is $400k at 60 years old. Although in another 5 years (when you reach 65), the annuity life will kick in paying you and spouse a monthly payout of $2.0k pm each or $48k pa combined.

Although the numbers may look good, they are not in today's dollars. In 15 years time, the $48k is probably equivalent to $30k today's value because of inflation.

I know it's convoluted, but it's all in the math.