I have thoughts about this, and apologize because I'm not succint.
One is when I look up your place as an individual potential guest, I can't see how many less than five star reviews you have. For comparison, there is a nearby place to you that also offers accomodations for two guests, for $78 US (Yours is double that), and they are rated the same as you on value (4.5), but also almost all the other areas are 4.5 stars as well. So by comparison, I would expect that you have a very nice place and go above and beyond to give guests a great experience. To me the overall 5 star rating and only slight ding on value represents a really quality listing that I would consider any day. The $32 US place next door to you seems to be a noncomparable because it looks like more of a hostel/commune experience. Compared to other area listings, you are not fairing any worse as far as recommendations go.
Also, when I look at airbnb's as a guest, I typically look at the photos first - yours are great. I look at the reviews, yours are fabulous, and I read the description quickly to see if it will fit our family - you have written a beautiful description. Finally, if it isn't instant book, since I usually book last minute, I look at response times - you are so responsive, and a super host too! The stars I am basically just considering anything with scores above 3 as being "comparable" in my search. It's the rest of the information that really helps me narrow down the final choice.
I agree with a previous commenter that says your level of bookings will tell you if your prices are too high.
I think it is possible, given the large number of truly budget Airbnb's available in Darwin some people may give you lower stars in value because you aren't offering a "value" (ie cheap) location, or because they themselves decided later "hmm, you know after this experience I would have been just as happy in someone's basement" or something like that.
So what I am trying to say is I don't think you should change prices based on a few lower star reviews for value because as customers fill these out, they may not realize how important they are to the hosts it terms of site ranking and stuff. And also, I think unless you see some drop in reservations you can keep price as is. Hosts may value stars more than guests, because guests only see the aggregate, not the individual.