What Smyth’s analysis shows is that the Spanish handling was more complicated than Montagu’s account suggested, with various Spanish authorities having different relationships to the material and different degrees of cooperation or resistance to German pressure to share it. The documents did reach German intelligence, but through a process that was less smooth and less fully under British control than the Montagu narrative implies.
The German military response to the material was also less total than some popular accounts suggest. Kesselring, who was actually responsible for defending the Mediterranean theater, remained convinced that Sicily was the most likely target. His memoirs and postwar testimony indicate that he did not abandon his assessment of Sicily as the likely objective, even after the Mincemeat material reached the command. He took the material seriously enough to adjust some defensive postures, but he did not entirely reorient his defensive planning.
What shifted, in the German assessment, was the probability distribution. Before Mincemeat, German intelligence might have assessed Sicily as 70% likely and other targets as sharing the remaining probability. After Mincemeat, the assessment might have shifted to 50% Sicily and larger shares going to Greece and Sardinia. This shift in probability, not a complete reversal of assessment, is what the historical evidence actually supports.
The impact of this probability shift on German military dispositions was real but not decisive by itself. The forces that were moved away from Sicily in response to the Mincemeat deception — particularly the 1st Panzer Division, which went to Greece and was not available to reinforce Sicily — represented a meaningful but not overwhelming reduction in the defensive capacity of the island. The forces that remained in Sicily were substantial and well-organized.