I recently made some enquiries by email to AMU and i think there are one or 2 errors in your assumptions that should be cleared up.
1. The "unforeseen tax" issue is one that EDEN will have to bear the brunt of not AMU shareholders.
2. There is no more negotiating to be done. The offer is on the table. Aside from the A$/US$ provisions the deal will stand as it is.
There is a perception of transaction risk in the market, i think Hartleys put it at about 40%. No surprise really. Eden offer is debt funded so as the A$ rises the deal gets more expensive for them and like everyone there will be a limit as to how much their financiers will pay.
AMU Price at posting:
26.5¢ Sentiment: Hold Disclosure: Held