Tron "Ledge" Discrepancy

[kdo]

Can anyone help regarding a question I have about the added "ledge" effect scene in the original 1982 "Tron."

Remastered Blu-ray & DVD: http://img541.imageshack.us/img541/7454/tron12bd.png
HDNET (and previous DVD transfers): http://img688.imageshack.us/img688/5169/tron12tv.png

About a week ago, I was flipping through channels and "Tron" was on the Showtime Family Network. I noticed there was a discrepancy between the Blu-ray version (as well as the remastered DVD that comes with it) and the transfer that is currently airing on television (even though it's full-screen).

On the Showtime version I DVR'd (which seems to have been taken from the same master as the Blu and new DVD), the upper and lower "ledge" effect is visible, but at no point during the scene is the top of Tron's helmet obstructed by it . I'm at a loss to explain the difference. As far as I know, the transfers for "Tron" floating around out there consist of the one used for the 1998 DVD (which is closest to how the film appeared theatrically), the 20th anniversary DVD (which had some tweaks, but no "ledge"), then the Blu-ray and DVD remaster that just came out (with the ledge effect and other minor tweaks/color alterations)...

From what I understand, some HDTV broadcasts, (which I never saw), were supposedly using the new master (that was created for the upcoming Blu) several months prior to the Blu being released. I don't know what's going on here, but all I know for sure is that the top of the "ledge" overhang is framed differently on the TV version than on the Blu, and it's not as cramped...

Is there a chance that Lisberger reworked the ledge sequence yet again for the Blu/DVD release? Does everyone else's Blu copy slightly cut off the top of Tron's helmet briefly during that scene? Mine does...does anyone have a copy that doesn't? I'd like to get to the bottom of this and would greatly appreciate any feedback or information!

Thanks!