Can someone explain the CanResuseTransform property of this interface to me?

I have an app that communicates over the network and I encrypt the
individual UDP packets which are sent and received from multiple clients.
Each has the same key and IV.

I guess my question is, do I need to create new encryptors and decryptors
for every packet?

Part of my concern is that the state of the encryptor/decryptor might change
as packets are encrypted. If that's the case, then if I encrypt a packet and
send it to client A and then encrypt an identical packet for client B, the
two packets will be different and only the first recipient will be able to
decrypt it.

I use the CryptoStream.FlushFinalBlock, so I'm assuming this resets the
states and will allow me to do what I want. I'd like to avoid the cost of
recreating the encryptor and decryptor for every packet.

Thanks.