I wrote a series about different encryption algorithms in the xDev magazine and performed the computations from scratch in Xojo (Feistel Network). If the algorithm uses the Feistel Network then encryption and decryption should take the exact same amount of time.
Although the encryption and decryption time is the same, I am not sure what Xojo does in the background to open, read, write, and close files, which can take a significant amount of time.
If the algorithm is running in memory, then it will be faster when compared with files.