Some items has 00 (or 00 00) in their offsets.
So we need to shift.
For example
Imagine your last item has this offset: 78 97 00
If you inject the code (the one in the first post) one the last 00 you see, you could corrupt the bag.
So instead of
78 97 C0 E5 4E E0 E5 4E 00 E6 4E 20 E6 4E 40 E6 4E (While thinking 00 is not from an item)
It should be
78 97 00 C0 E5 4E E0 E5 4E 00 E6 4E 20 E6 4E 40 E6 4E
Or even
78 97 00 00 C0 E5 4E E0 E5 4E 00 E6 4E 20 E6 4E 40 E6 4E
(Because maybe 78 is the last offset from the 2nd last item, and the offset for the very last item is 97 00 00).
Due to my english, I don't know if I explained well.
Try to read this post