I am doing a similar trip later this month. My flight is SIN-CMB-SIN with a 1:25 stopover in CMB.

SQ told me that I can collect my CMB-SIN boarding pass in SIN before I travel to CMB, effectively checking me in for the return flight before I arrive in CMB.

I wanted to make doubly sure the information was correct so I phoned SQ back on another day and spoke with a different agent. Both agents concur. I can't see what the problem is...

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Latitudes.

For my part, I travel not to go anywhere, but to go. I travel for travel’s sake. The great affair is to move; to feel the needs and hitches of our life more nearly; to come down off this feather-bed of civilisation, and find the globe granite underfoot and strewn with cutting flints.
Robert Louis Stevenson (1850–1894)