Refrigeration protection: differences in specifications depending on model (DS4/308/408/Astra)

In another topic the topic came up in the margin and a short research led to questions. There are model-specific cold protection inserts for the radiator grille for these vehicles. The manuals make certain limitations to the motorizations: In DS4 and 308 the cold protection is multipart, while for 408 and Astra there is only a smaller version for the lower area. Opinions about this? Manuals as PDF: , , and .