I answered you PM
The byte swap is needed always to write a BIN that was read/edited using tuning software.
Tuning software uses a binary format different than the one used when the chip is read with a external programmer.

If you read the chip from a working PCM with a programmer and you try to open it in TC it will not open. You need to byte swap it first.
The opposite is also true. If you have a bin saved in TC/Winflash and write it directly to the PCM the write will complete without error but the PCM will not boot. You need to byte swap it before writing it.

Hope this answers your question