Originally Posted by MKE-MR
This is mostly valid. The SFO-GRU-SFO is a surcharge, fairly hefty, if you weren't aware (and I'm not sure how you do this other than SFO-ORD-GRU-ORD, in which case I don't think you can go back to SFO). Otherwise, I'm not sure about the DXB-CMB-MLE. You could, however, go DXB-CMB(stop)-DXB(transit)-MLE-DXB(transit)-BKK
You can't go through SIN twice. You still have it twice, and in addition you can't get from SIN-BKK anyway, I'm afraid, which is why the DXB-BKK instead in the example above.
You're close, and it can be a pretty good bang for the buck if you route it well, but you need to be quite careful and read over the fare rules a bit more.
Thanks! It would be so nice if someone can hint about the taxes / surcharges for the above routing (with corrections as you have suggested) for Y ticket. I suspect they will come to be more than 50% of the base fare.