Losa obtained the meditation method from the Knight Order — but it was no different from what Jeanne taught him, in many places it was even more obscure and difficult to understand, not as straightforward as what Jeanne taught.
After all, the Holy Church Knight Order where Jeanne belonged was considered the first knight order in Europe at that time, rising from the ruins of the Templar Order annihilated by the King of France. It's understandable that the meditation method advanced even further.
Thus, the soldiers under his command failing to master the key of Holy Light cannot be due to the meditation method.
Leaving the Knight Order's camp, Losa went straight to inspect the camps of the Flemish spearmen and the Swiss halberdiers on the outskirts of the city.
