LPT: Revenue "HeatMap" Valuation: Why might post-2000 property be worth less?

Just checked Revenue online LPT guide for a rural area. Every house category is in band 2, except semi-detached and terraced house built post 2000, which are in band 1. Why would post 2000 properties be valued less than pre 2000? Do they know something about build quality or size that they're not saying? I didn't think Revenue had analysed those particular criteria anyway.

Remember that technical paper on the model that I linked you to the other day? (http://www.revenue.ie/en/tax/lpt/valuation-technical-paper.pdf)

According to it, the model was populated with year of construction from the Geo-directory: "Derived from the “create date” field. May not necessarily reflect the year of the construction and is only included as a binary variable: 0 for pre-2000 and 1 for post-2000."

Under Para. 4.4 they go on to say:

"Model performance is slightly better with more recently constructed properties (post-2000) than older properties."​

I'm afraid I don't understand your answer.

The answer above basically says that post 2000 builds should generally be better/more valuable than pre 2000 builds. Probably due to updated building regulations that came in around then I presume?