I need to go back at what I said about Cwb/Cwc:

They are indeed different but the simplifications you made abolishes these differences since they fit in the same temperature categories. The only difference is : Cwc is colder (but that should be obvious)
I suggest that you just ignore it.

but here's the details in case your curious:

Cwb
• Average temperature of the 3 coldest months between 0 °C and 18 °C
• Average temperature of the 4 hottest months between 10°C and 22 °C


Cwc:
• Average temperature of the 3 coldest months between 0 °C and 18 °C
• Average temperature of the 3 hottest months between 10°C and 22 °C
• No more than 3 months with average temperature > 10 °C