Geez that's harsh
Whereabouts did you go on exchange? I was considering it but if it messes up your WAM/GPA then it might be a bit of a risk...
I went to Penn, which is ranked like x higher than UoM in the world. I think Penn is like 15 and Melb is like 30 something. The supposed rule is that if your uni isn't in the top 100 you get an extra 5% docked off the total average for your GPA calculation but don't quote me on that part - there is some additional reduction if your university doesn't rank highly internationally in research. The best you can do at another uni, even with 100% is a 92% score when it gets converted. However, this is only ever relevant if you want to do postgrad study for which entry is INTERNALLY ASSESSED by Melbourne University. The JD might fall under that umbrella - do you know if they use SGPA, or another GPA calc system?
For eg. if you're applying to Med the same reductions do not apply - the GPA will be assessed under a different system.
And if you're applying for a job with your exchange transcript your employer can just see what the university in question gave you, and judge for themselves.
Melbourne won't state the reduced grades on your Melbourne transcript - it only becomes relevant when you apply for something like a PhD scholarship, Honours, etc (all of the things I'm applying for lulz). Also Engineering would be affected.
Nobody tells you about this shit before you go on exchange, and I feel like they should have to. For eg I probs wouldn't have taken third year classes o/s if I had known because those credits count towards my PhD scholarship applications and I could have done better than a 92 here (what the two third year subjects I have will be counted as). However, overall it only brings down my GPA around 1-2% which isn't too big a deal. I would never just /not/ go on exchange because of the reductive GPA policies. It's definitely, definitely worth it - even if your scores do count a little less. You need to keep in mind that Melbourne grades very harshly anyway - if you go o/s it's often much easier to get 100% in subjects. 80% in American universities is usually like a B, not a H1. 80% converted back would therefore come in around a H3. But if you're getting 80s here, you're often capable of 90s or more there, with the same amount of work. Just depends on how much work you're willing to put in on exchange. With exchange you can often win out with the 'overlap' stuff that comes with it - eg when I took genetics there was a lot of overlap with our own first year genetics shit which meant I could ace it without studying it pretty much. Choose your subjects wisely and the GPA thing becomes less ridiculous.