2004 6.0 ---> Clogged Turbo?

[Scotter06]

2004 6.0 with 68K on it, its been to the dealer numerous times but most recent (yesterday) took it in due to really rough start ups, coolant leak, white smoke, and intermittent exhaust smell in the cab. After doing some thread searching I figured it would be the EGR or a head gasket.

Got a call from the dealer today, told me my turbo was clogged and had a hose leak. He said the turbo had to be cleaned and the hose to be replaced at my cost. Now im not the most educated on alot of the technicals but I like to think I understand most things, I dont understand why my turbo would be clogged, or if this is the problem. Also, I would like to know why its not covered under the 100K warranty, dealer told me because its not a mechanical problem and that it is essentially poor design. ??? If its something that I didnt abuse and could not have prevented why shouldn't ford cover it?

Cliffs:
2004 6.0 with 68K mi
Clogged Turbo -->
What causes it and why isn't it covered?

Thanks to anyone who can help