@ stevendorechester

First, thanks for starting this thread with a title that states the topic (and question)

As others have posted, this issue has been a around a long time. Transpacificflyer and I, among others, have posted examples of AC fares to SIN, where the AC over-water is in J, but the cnx from HKG on SQ or the cnx from NRT on NH, both have you sitting in Y. Some of these fares were $7,500. These were not only on the website, but when I called in about it, one AC res agent said "well, that is what SQ sells us".

So my options became much more clear when I found I could fly CX YYZ-HKG-SIN on a seamless cnx, in J all the way, four thousands less.

Similarly, I had been discussing the AY fare that is almost $4,000 LESS than AC and at least $1,500 less than CX. Sure, you need to BA to LHR then AY to HEL and onward to SIN. Well, not everyone is one of those "I have to be there yesterday" kind of people. (and for those who have status with a OW airline, there is certainly no loss with either the CX or AY option)

As noted above by others, I am quite sure a competent TA can book an AC J ticket with a J cnx. And we know from others here that SIN is not the only destination with a cnx where AC pricing for the partner connection is a little over the top (to be gracious).

just saying.....