Recently received an invitation to upgrade my flights to SIN. I was flying MNL-HKG-SIN RT. For the MNL-HKG sector the fair chance costs about US$485 for Y to J upgrade, while HKG-SIN sectors was at US$865+11 per way again for Y to J upgrade. What doesn't make any sense is if I sum all the cost, it would be more expensive than buying an I class RT ticket