Are we talking about paying for revenue tickets with miles & cash (i.e. discount on the cash price of revenue ticket by using miles), or paying for redemption tickets with miles & cash (when, for example, not enough miles to redeem award)?

The conversion rate is terrible if it's the former, since you need to redeem 100,000 miles for a base fare of SGD 1087 (barely one-way Y), whereas the same 100,000 miles is enough for a one-way in suites Europe-SIN...