"Mono" bus on TF series available?

TF series has "Sub" bus instead of "Mono".
The Sub bus is designed little differently but you can use it as a Mono bus.

Open ASSIGN screen and bring Sub level to nominal (0.00), now the channel is assigned to the bus with same level as Stereo main bus.
(Actually, they may differ depends on PAN position.)

Advantage of this Sub bus design against Mono bus on an analog mixer is:

• Different level to the Sub bus, channel by channel.
  For example, sending more low end from a kick drum than a bass guitar because of a bass amp on the stage.
• Sub bus master level linked to Stereo main bus master.
  It means you don't have to take care of each of faders every time you change FoH level. The other automatically follows. (Do you remember there was a part to link fader caps physically. or, a rubber band...:-))
  To operate them separately, go to System Setup --> Bus Setup and turn Stereo/Sub Level Link off.
• LPF and 2-band EQ available.
  The high band of the EQ can be changed to another LPF. By using those two filters, you can actually create -24dB/oct LPF.

Many of us use an aux bus for sub-woofer send for flexible level control of each channel. But we don't have a aux master fader level linked with Stereo master. This is to solve the problem.
Any questions? Let me know.
Shaun