In general the FTPS (FTPES) does not necessarily mean that data is encrypted. Though typically it is encrypted (as is in this particular instance).
Your client requested Private Data Channel Protection Level using the PROT P
command. The Private level means that the data will be integrity and confidentiality protected.
As the server acknowledged the request (the response 200 PROT now Private
), the data are encrypted (= confidentiality protection).
For details see the RFC 2228.