I have 4 intra-Europe sectors on award tickets (LX and OS) issued by AirNZ for travel in late Jul. Are these upgradeable through PlusGrade?

I am more just curious than seriously interested. I flew BER-FRA on LH last year on a cash economy L fare, upgraded into Euro-biz (fully aware of what it would be) and was 'happy' to pay the instant upgrade fee as the e-tix was re-issued into P class. This fare class actually earns into AirNZ's lousy program, as the initial economy L class would have earned nothing.