As described so simply in the L7 Owner's Manual Supplement, there are many forms of bi-wiring but none of them are true bi-amp. My only experience with bi-amped JBLs is with my 4345 which were built intentionally to delete the bi-amp switch so they must be bi-amped. Which requires an electronic crossover. I'm not familiar with the XPLs to know if they work the same way as the L7 but it seems from your message that they have a switch where for the L7 an internal wiring mod must be made to properly bi-amp them. Not sure what's required to achieve the same advantage on the 250Ti.