A genuine fixed-price contract:

• Includes site cost after a soil test - NOT "estimated site cost".
• Has all PC sums and prime-cost items priced out at contract stage.
• Has all council contributions and encroachment fees included.
• Has an itemised variation policy with unit-rate caps.
• Includes a genuinely built-in contingency for weather delays.

• Provisional site cost - the number goes up after soil test. Usual jump: $8k-$45k on flat blocks, $30k-$120k on sloping.
• PC sum items - electrical, floor coverings, lighting, tapware. Usually 25-40% underpriced in "base" contracts.
• Prime-cost allowances - benchtops, tiles, appliances. Same pattern.
• Council contributions - can be $8k-$25k on new-estate blocks.
• Excluded landscaping / driveway / fencing - often not included in "turnkey".

Reputation for pricing accuracy varies widely. Volume/project builders who consistently rank well on this signal in BuildPilot's data:

• Fairmont Homes - long track record of fixed-price contracts holding.
• Rossdale Homes - regional accountability, low variation record.
• Bradford Homes - fixed-price "Embrace" contracts, backed by Scott Salisbury Group.
• La Vida Homes - accurate pricing is a stated positioning claim.
• Format Homes - consistently transparent pricing across the northern growth corridor.

Custom builders can also hold fixed price - the tier is not the point. Contract language and variation policy is.

1. Get a full quote with the soil test result already applied.
2. Ask for a per-PC-item breakdown of every prime-cost allowance.
3. Read the variation clause. If variations are "at builder discretion" or use "market rate at time of variation", walk.
4. Ask for the last 3 fixed-price contracts the builder signed and their final invoiced totals. A 3-5% variance is normal; 15%+ is a red flag.
5. Get an independent pre-contract review from a construction lawyer. Costs $600-$1,200. Saves years of pain.