Does your audio interface actually have a differential balanced input? Many have "impedance balanced" inputs where the ring terminal is just connected to a resistance matching the input resistance on the tip terminal. It will attenuate 6 dB as you said, but a balanced source through a balanced cable will "see" a balanced input so the cable is less likely to pick up induced noise.
The line inputs on my interface are selectable (+4 dBu/-10 dBv), and I've found that the Rev2's unbalanced output is hot enough that some patches will clip on the -10 dBv setting, so I use +4. Losing 6dB due to the unbalanced output is probably not going to be an issue.
Unless you need the balanced connection for noise immunity (e.g. if you have a long cable between the Rev2 and your interface), I wouldn't worry too much about it. If you really want to use a balanced cable, maybe add some good signal transformers (or DI units if you must) as close as possible to the Rev2 end of the line?