Done.
Reading a bit in dePas, I was reminded that there was a promise by Jean Sans Peur to not change the composition of the coins in the Burgundian Low Countries for 15 years.
If I recall correctly, when Philippe le Bon came to power, he mostly upheld the promise, but found a few ways to “cheat,” and maybe this striking of coins in Namur was part of this (I think he also struck ecus of lower titre in some new mints).
Anyhow, yes, as the coin is sturck in the name of the Count of Flanders, and says it is “New coin of Flanders reverse” it makes sense to have it there, with a new date line and some comments.