House/land build variations

Hi

I have a query concerning a new house and land build that I need to check if all is above board.  Contracts were signed earlier this year. Slab has not been laid as yet.

My daughter and her partner signed contracts with Mimosa Homes for a land/house package.  Mimosa has arranged their own developer, which in communications, they refer to the developer as being my daughters developer. I think a clever ‘keeping arms length’ distance with this current issue that Mimosa are employing.

Recently the developer has advise the house requires two variations:

1/  Above the double garage door, the developer requires it to be a brick infill with metal lintel and not a wooden facade as per standard Mimosa house design.
2/  The retaining wall required is due to the fall on the block and is required as per engineering requirement. A slit pit is required with a retaining wall as it is the draining.

Important notes I’ll share with you. The

– house is a standard Mimosa Drysdale design which comes with both, brick façade above the garage roller door and wooden facade above the roller doors. Customer picks their choice of façade.
– land is flat to the eye and it makes sense there must be fall but it’s not noticeable to the untrained eye.  All blocks surrounding the land are flat.

Both variations are costed at $4600.  My questions are:

1/  As this is a standard Mimosa design and they are using their own developer, they should be aware of the developer requirements from previous builds and if these are true, at what point should Mimosa have at commencement of house design and planning, guide and included these into the design to avoid unnecessary variation delays and extra unexpected costs?

2/  Is this becoming common practice for Developers and builders to add these variations to extract more money from unsuspecting customers.

3/  Who and where does my daughter go to next to have an independent review, is this time to have our own building inspector be part of the process.

Overall, if this is a correct process and all above board, then ok, we will need to pay it and move on.  I just think that there is some creative work going on here to get more money out of a build for unnecessary items, or items which Mimosa is aware of and their standard house packages have design flaws which they are not taking accountability of.

Please share your thoughts.