In 18th century France a double bevelled tool even had a different name from a single bevelled tool. The idea that 18th century woodworkers were so clumsy that they could not maintain a single bevel tool is just not supported by evidence.
Figure 9 appears to be hollow ground whereas figure 11 appears to be flat ground for the full length of both sides.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)