Originally Posted by g289t

So the price could be F for the entire trip, even though 70% of it is operated by an aircraft without F? Is that what I'm reading?

This is how I calculated the trip:
JFK-SIN in J: 111,500
JFK-SIN-SYD in J: 145,500
Difference: 34,500

SIN-SYD in J: 68,500
SIN-SYD in F: 155,000
Difference: 86,500
I assume the difference as the upgrade price, but I don't actually know if that is how it works.

So if I take JFK-SIN-SYD @ 145,500 and add the upgrade price for SIN-SYD of 86,500, it comes out to 232,000.

Using the separate prices of JFK-SIN in J plus SIN-SYD in F comes out to 266,500 total. If I could book the entire trip in J and upgrade the one segment to F at 86,500, it would save 34,500.

Maybe 34,500 (it will be me and my wife so x2) isn't worth messing around and I should just book separate.

On a side note, this month Amex has a 20% transfer bonus to SQ, at least for some people. It seems to be targeted.