I'm not an accountant ... but is this always true ? Isn't the software that underlies a Stock Exchange looked upon in the same way that, say, the brand value is ? If the development that has now been abandoned had turned out to be raging success wouldn't this have increased the value of the ASX ? And, in that case, wouldn't that software be treated as something which partially constituted the value of the ASX in the same way that patents held by ASX would have a value ?
Even if their comments were sincere they wouldn't be the first suit to have a limited understanding of the Pareto principle.
Also if there's a new CEO they are certainly going to want to clear out the cupboards, hence the call to Accenture (doubtless with some significant guidance on what the client expected in the report).
It's not clear to me whether the $A250M was the direct costs to the Exchange (ie invoices + ASX staff time) or the value which the Exchange was carrying the software on their books at ?
As I say I'm not an accountant ;-)