The impression I get - one I think is shared by others studying the glyphs - is that corrections were usually done by kind of making the best of it and still trying to form the mistake into the desired glyph. This is something we can only study when we understand the glyphs better though.
When people say there are no corrections, they usually mean that there are few signs of "messy" correction like scratching, obvious overwriting, obvious erasing....
Edit: I somehow missed Rene's quote, which explains everything.
When people say there are no corrections, they usually mean that there are few signs of "messy" correction like scratching, obvious overwriting, obvious erasing....
Edit: I somehow missed Rene's quote, which explains everything.