It happens. Lots of maintenace issues, ie. oil used and service intervals, poor fuel quality and also the new fuel issue ULSD. I personally have not seen any issues with the ULSD fuel yet, but others have. I always use the new Stanadyne additive with every fill up just incase, but none the less it could just have beeen a bad injector. How did you determine the piston was bad, did you pull the head and look, did you check blow by from crankcase vent?
2000 F350 PSD CC 4X4 AT LWB 3.73s 173,000AFE STAGE I, TN.BB, EIS 200CC HYBRIDS F5 DP TUNER 4" TURBO BACK, AEROTURBINE 4040XL, 5" STACKS, ISSPRO GAUGES,PRE AND POST TURBO PYRO, SCANGAUGE.