The flying signal is unchanged. Can the mobile phone number be changed to Unicom or mobile phone number?

Fetion has a free mobile phone number change service, which means that your flight signal can be changed and directly bound to another mobile phone number. This means that your Fetion friends can follow your new number one at a time.

There is a problem here. Can the phone number of the original flying signal be replaced with the number of Unicom Telecom?

In theory, since Fetion is open for registration, the service for replacing the mobile phone number should also be open to both Unicom and telecom users. But as it turns out, no, Fetion's service to replace the mobile number can only be replaced with other mobile numbers.
Change the phone number must be the mobile phone number

This is a BUG in my opinion. Because this directly leads the author to spend a lot of effort to export the phone number of the original flying signal, and then join in batches, all the original Fetion friends have to agree to add the author as a Fetion friend. The final result is exactly the same. Since the effect is the same, why is it "replace the phone number"? This feature is not open?