AOG's NTA

I have been running some numbers on AOG given the NTA discount (which appears, at least on the face of it, to make this a no brainer investment). BTW - I'm not phased by a 23% owner that is part of the family controlling Sun Hung Kai - of course they will act in their own interests but this is a very large and highly successful property investor/developer across APAC, particularly in Hong Kong.
I was however very interested in reading the detail of the AOG financial statements. It mentions in the notes to the accounts that the 'aggregate current market value of the individual retirement units is $5,061m', versus the carrying value of $6,159m. The key issue for AOG appears to be the risk that regulation will reduce the amount that they can make from deferred management fees/profits from property transfers. Interestingly, if we conservatively assume that regulation reduces the cashflows from these activities, and results in the valuations of these properties moving back to the market value of the individual units, the NTA would fall from $3.92 to $2.03, in line with the current share price.