With regards to the 10K off is that off of the purchase price or a rebate from the developer?
If it's off of the purchase price you could probably offer a lower amount than that advised as there's clearly some motivation there from the agent.
Suss it out; call the selling agent again and say:
"I'm just not able to come up to the amount you've suggested but i'm interested in this and another property (make sure you have another address at front of mind). What is the lowest price you would be confident in taking to the Vendor?"
When buying from a developer you can save money if you approach them directly. The reason for it is you'll remove the marketing and commission costs from your purchase price which in this case could be around $20K+
Sometimes this is not possible as it depends on the authority for the selling agent. If you're interested in doing that though perhaps approach a buyer's agent in your area and see if they know the developer.
We buy off the plan properties for our client's PPORs quite often and can usually save a substantial amount for them by dealing directly.