Best explanation I've seen yet:
From F150online.com
On the issue of last date flashed, in speaking to several Ford Service employees, we have found dealers can only look at and record last date flashed to a specific WDS tool, the user would input the last flashed data, and a Predator has no such option, and would thus not leave this signature in the vehicle. If a Ford dealer would plug the WDS back in later, after a Predator was used, all he would see in last date flashed would be the data he had put in when HE last flashed it, Predator would not show up if it had been used and restored to stock even 10 minutes before the vehicle was brought to the dealer. Another dealer could not even see the last date flashed when using a different WDS tool, unless it was loaded to the nationwide system used by Ford which we are told is only done by specific request made by Ford.
This is result of recent conversations with Ford and we feel this information is accurate, keep in mind this is hear say to some extent. If we can find evidence to the contrary we will relay it ASAP.
Thanks,
Nick Spinelli
DiabloSport Sales Manager
From F150online.com