I just did a quick trip to Milan from Melbourne on Thai (MEL-BKK-MXP), business class.
Credited to my Air NZ account was 150 for MEL-BKK and only 95 for BKK-MXP.

Now the flying time is longer, and distance greater, for BKK-MXP than for the MEL-BKK. A large number of frequent flyer programs base the earnings on miles travelled, but so Air NZ in this case.
I know that if I flew to HKG, then on an NZ flight to LHR, and then to MXP, my earnings would have been much higher because of the use of NZ metal. This would have been a much longer flight coupled with the hassle of transfer at LHR. Something to avoid.

The large earning difference between the two flights, MEL-BKK and BKK-MXP, seems a little unfair to me.

BTW, the TG 777-200 was fine up front, though the business seat does not match BP on NZ with respect to space and quality of wines (I do enjoy NZ whites ).