Yeh, I've got a bit of time in the ol' mixmaster, bloody good aeroplane, too.
Let us list the facts in isolation, maybe we could all see what the deal is then, because it really depends in which context the question is asked.
The mixmaster is a multi-engined aeroplane.
You log such time in the "multi" columns in your logbook, both in Australia and in New Zealand. In this context "multi" refers both to centreline thrust and non-centreline thrust multi-engined aeroplanes.
Now, here is where it gets confusing......
Despite this time being correctly logged in the "multi" column, such time DOES NOT COUNT toward the issue of a higher licence or rating WHERE THAT QUALIFICATION REQUIRES A MINIMUM AMOUNT OF MULTI TIME. In this context "multi" means non-centreline thrust multi-engined aeroplanes only.
Thus, the minimum time required for the next qualification must have been achieved on a non-centreline thrust multi-engined aeroplane. This includes the first multi-engined conversion (in NZ, 5.0 hours in a non-centreline thrust multi-engined aeroplane), multi-engined instrument rating (no minimum hours requirement if you already have a single-engined instrumant rating, but the multi test must be conducted in a non-centreline thrust multi-engined aeroplane), and so on.
Not sure whether it is clearer now, probably not, knowing me, but there you go. Of course if I have got something wrong, I will stand corrected.
Happy flying in the 337, the safest twin I ever flew.
dh