Texas property tax assessed value for newly constructed home

[Roger Malcolm]

Curious because of how unusually large it is, I looked up a home that has been under constructed all year and appears to be finished.  By all appearances, construction is finished. Landscaping has been installed, and few contractors go to it anymore - it looks to just be inside painters occasionally.    The home is twice to one and half sizes larger than already large homes near it, yet its assessed 2024 improved value is much lower than the assessed value of the smaller homes around it.  

Looking into how new construction is valued for property tax in Texas, the cost basis is the norm.  The assessed value of the improvement is a fraction of what the construction cost likely were.  For example, on a sq ft basis, the assessed value for this new home is $61.  That is almost one third of builder-grade construction cost in Texas, which are around $120 to $165 per sq foot,  and down to as low as 1/5 of the luxury market, which is  $200 to $300 per sq foot. 

What would cause the county to value the assessed value that low?  Is custom home  construction likely on the honor system and the county just took the word of the home owner?