Just a bit of background. Our block of land is in S/Morang (Melbourne) with a frontage of 21.5m and 45m in length. The slope runs up from front to back and has a 2.5m-3m slope on the building site alone (5m across whole block) Our soil tests have come back M class and we are building a double storey home with a custom home builder- approx. 41sq. We are still awaiting our plans to be drawn up.
Our customer service rep has told us that we should expect a site cost of at least $50,000 once the costings have been completed.

We were hoping to build on stumps but now im a bit worried that this may blow the site costs out even more!

Do these costs seem a bit steep or is this the norm? Would anyone like to share their experiences with building on a similar block of land?
Love to hear your thoughts.