The rates notice is the last thing I would accept as proof of a valuation. Some councils are ok some are way off and I am not going to work out which council I can trust. If the trustee wanted to use the rates notice as a bases I would preference them to go to say http://house.ksou.cn/ and pick 3 comparatives. It would give a better result.
PH, commercial judgement to be applied, for instance in Melbourne CIV is pretty accurate across most councils. If it smells bad, commercial judgement comes in......depends on your knowledge of the area. In the olden days with large scale audits we insisted on curbside annually with full independent valuation every 3 years, surprised that the ATO is quite relaxed given many SMSFs are including property at cost......
Cheers mate