article assumes specs are known. they might be for some kind of brochureware but for any serious work they never are, and in business reqs change day to day. 60% of software features are never used - so that&#x27;s 60% overspend right there. there&#x27;s no reason not to do fixed cost agile (personally wouldn&#x27;t do it any other way). trying to fix scope otoh is just bad business from the get go - a) you might have target outcomes but you don&#x27;t know exactly what you&#x27;re going to need to get there b) useful software tends to be ongoing in terms of reqs