If you looking for decent capital gains from FAX, my advice is look elsewhere. Closed End funds in general pay out the max. in current income, principle value in general is secondary in what I've seen.
The US bond market has exploded on the upside in the last 10-15 years, but look at the NAV's of most bond funds, down. Over the long term they drop. If bond rates went up a lot in the next 5 years I'd expect most bond fund to decrease to almost nothing after payout and bond value drops. DOn't let that happen to your money.
If you want to secure your principle better then you may buy the bonds directly as they have a definite maturity. Otherwise use stop losses and move on. These are not Bank CD alternatives but more like stocks, iMO. Have a fail safe system in mind to protect your principle.
IMO, if the AUD goes up a lot then you'll see dividend increases, NOT money reinvested to protect NAV value. It's the nature of the beast.