Final answer:
The BCD (Billing Cycle Date) for an Xfinity Mobile account with multiple devices is determined when the first device is activated. All subsequent devices on the account follow the same BCD, which remains unchangeable even if new devices are added.
Step-by-step explanation:
The BCD, or Billing Cycle Date, for an Xfinity Mobile account with multiple devices is determined at the start when the first device is activated. The day this first device becomes active becomes the BCD for the entire account. This means that all subsequent devices added to this Xfinity Mobile account will follow this same BCD. It's important to remember that the BCD is not alterable even if additional devices are added later.
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