I worked for EMC through the acquisition by Dell. I spoke with a someone in Dell MFG about their test process. In short, they test as configured by the customer. We were discussing a blade server. I asked what happens if a customer buys an additional blade and that slot on the backplane doesn’t work, because it wasn’t tested? The answer: we get them a new backplane really quickly. Dell is all about removing cost from the business and that means they made the calculation that it’s cheaper to test as configured and pay for the few cases where someone upgrades and has an issue, versus test everyone’s machine comprehensively. Needless to say, this wasn’t the EMC way. So yes, it’s expensive to overnight a new part to customers, but someone has done the ROI and figured out that is cheaper than testing every system for every anticipated problem.