So I've been working on getting into more hardware repairs, and specifically component level repairs. In doing so, I've been researching the GPU issues that many machines have that require either a reflow or reball to fix. It seems to be that the general consensus for laptops is that a reflow is a temporary fix, and could come back in a week, month or a year. As I understand it this is due to the lead-free solder used which becomes brittle overtime, cracks, and oxidizes, causing the loss of contact from the socket. 

That seems to be where reballing comes into play. By replacing it with lead solder, you eliminate, or at least, substantially reduce this problem. This in turn provides a better, longer lasting repair. Do I understand the situation correctly, or is there something more to it? The reason I asked, is because it seems like the xbox 360 suffers from the same fate. In researching xbox 360 repairs, the consensus seems to be more that a reball is unnecessary and won't provide any more that a proper reflow will. If the laptops and xbox's suffer from the same problem, I.e lead-free solder on the GPU's BGA, why would there be different resolutions between them?

I have seen people say that reballing will provide a better fix than reflowing the xbox, but it seems to be leaning on the side of reflowing vs reballing. Is it a cost thing, as in the xbox costs a lot less than a laptop, so paying more for the reball isn't worth it? Anyone with insight care to elaborate?
watch this video
http://www.youtube.com/watch?v=7xwHr6KoQC8