Aside: The crossover does not "dissipate the extra power as heat".
As a matter of fact, it does. Some is burned off as heat via the resistive component of pass-through inductors, some by the shunting of out of bandwidth frequencies to ground. The technical name for the power dissipated by a crossover is 'insertion loss'. With well designed and constructed crossovers it tends to be minor, but with poorly designed and built crossovers it can be as much as 2dB. That's about a 35% power loss.
Yes, it does. In the Audessey setup the FIRST thing it wants to know is if the speakers are "standard" or "bi-amped".
I can also set the crossovers for every speaker except sub at full-range, 40, 60, 80, 100, and 120 hz. If the mains are full range, I can choose the option for setting double-bass output.
If it's not allowing you to set the crossover frequency between the midbasses and tweeters, which would occur somewhere between 1.5kHz and 3kHz on average, it's not bi-amping. The only crossover you're setting is that between the subs and mains.
I still don't get why passive bi amping doesn't double the wattage delivered.
Watts don't matter. Voltage swing does. The average consumer doesn't know that, a fact that the marketeers take advantage of when trying to convince them of the non-existent benefits of passive bi-amping.
All I wanted to know was does this passive bi-amping feature deliver more wattage to my speakers
The pertinent question is whether it delivers more voltage swing. The answer is no.
Would this yield better sound quality than high quality crossover components?
The main advantage to active versus passive crossovers is lower distortion, both THD and IMD, from the amps. Another benefit is that actives tend to have much steeper filter slopes, which reduces THD and IMD sourced by the drivers themselves. Next comes lower the lower THD and IMD that an active crossover itself has compared to a passive. The last benefit is the lack of insertion loss created by passives.