Is there a way to book a flight with two different classes in out- and inbound leg with SQ? If I select economy, it won't show me any option to buy a business rate, but maybe I'm overlooking something (also took me a while to find it on Turkish).

I want to book a flight SIN-DPS. It's only a 2h45 hop, so Eco normally should be good enough. But I fly with the +1, we come from a 13h flight to SIN and will only arrive in DPS past midnight. Would like to enjoy the Silverkris Lounge in Singapore, plus a decent evening snack. Flying back however is a flight after breakfast and I should get into the same lounge as every business guest with *G anyways. So not much benefit, and I could save a few bucks (though the difference isn't huge as Eco is fairly expensive).

Maybe it's just not possible, but would be happy to learn from frequent SQ customers. Thanks!