Ripple Can't Be Transferred Between Bittrex Accounts

I only found out now that Bittrex is not allowing transfer of Ripples (XRP) from one Bittrex Account to another.

Below is the screenshot of the error message I got when I tried transferring.

Due to this incident, I deduced a theory that "all the generated wallets in our accounts are not really the containers of all the coins we own and placed at Bittrex.." They are all owned by Bittrex, but the addresses have references to our accounts.

This deduction also stemmed out of the ledger statement of transactions that transpired on my ETH wallet address at Bittrex, as shown on the screenshot below.

In other words, the wallets in our accounts are not OUR wallet addresses.. Instead, Bittrex just lets us borrow wallet addresses, and the coins sent to us via those wallet addresses are then converted into database entries (or accounting entries) of the coins we own.

These entries (including all transactions we ever did with them to date) are then listed on our private accounts.

One question that popped up is this -> how come ETH or ANS (based on my experience) can easily be transferred from one Trex account to another?

I haven't tried transferring coins out of Bittrex.. Hopefully the transfer out would be as seamless as transferring into the platform.