This is, IMO the 'deal breaker'. The cost is not in support per se, the cost is in writing off their existing software catalogue and implementing/buying another one and the changes in workflow / training requirements that may impose, even given it's possible. If they can show they'd spend less re-equipping with & supporting tablets than they would on maintaining an existing desktop/laptop based infrastructure and that it wouldn't significantly impact efficiency, then obviously it's the smart thing to do. We don't really have the numbers available to us to make that decision in their case, frankly.