The file looks OK, someone has already wiped all of the IMMO ID/VIN data from the ECU. All of the FF's look a little strange but its probably fine.
Is there any chance the ECU already has a tuned file, and possibly an immo off in the flash, did you try it out?
If not I think your immo off changes sound right but I don't do rows and columns. You should be going by the address as its easy to change the view to any # of columns.
0x12 change 01 to 02
0x1E change 23 to 22
0x22 change 01 to 02
0x2E change 22 to 21
All of my DL ECU's show FF where the Vin would be with the Later immo 3 would have it.
that includes stock and tuned files.