ikea sale - irr discussion at 20%

Seems the Ikea sale causing a bit of confusion (to me too) so thought to address it as it's own discussion and for comments.

Doing a bit of research and found:

Tempe site purchase - Two parcels of land - refer asx ann 4th April 07 - 46 million

Parcel 1) 5.5ha site - $30 million paid
Parcel 2) 2.7ha site - $16 million paid

A news article regarding potential sale to Ikea, September 4th 2008 SMH, however this as it mentions was for one parcel of land not the two at that time:

http://www.smh.com.au/lifestyle/homestyle/new-megastore-for-ikea-20090403-9pdi.html

"Valad later bought a larger parcel of land there including the area Ikea had wanted and now plans to sell a section to the retailer."

"Ikea's chief executive, Kent Nordin, confirmed yesterday the company was close to signing a $35 million-plus deal to buy almost 40,000 square metres from property group Valad."

Now looking at the recent announcement stating approximately 10ha sold (so now both original parcels together I assume, as the first original was only 5.5ha but that was store only, games changed now) and based on IRR at 20% over life of the projects capital investment "should" have sold both for around 55 million. Given Ikea were willing to part with 35+ million for one parcel for a store only as per the article, and if they have instead bought both as it indicates their making it their headquarters and adding warehousing, staff amenities 1700 car parks etc I think this is a reasonable conclusion.

I guess it comes down to is IRR stated off the original purchase price or a written down book value.. I would have thought though that IRR is the flat return rate over life of projects capital from the start.

Thoughts?