The Directors' assessment of fair value of each investment property takes into account latest independent valuations, with updates taking into account any changes in estimated yield, underlying income and valuations of comparable properties. In determining the fair value, the capitalisation of net income method and / or the discounting of future net cash flows to their present value have been used, which are based upon assumptions and judgements in relation to future rental income, property capitalisation rate or estimated yield and make reference to market evidence of transaction prices for similar properties

According to the paragraph above explain the flexibility management has available in the determination of investment property values?