Fryette 2502 Power Amp Question ?

[sweetrock]

Hi there,
I always use my power amp mono and use the channel B to drive my 412 cab or cabs .
Now ,
For years I only connect the cab or cabs to channel B speaker outs , and the channel A is power off and the channel A's speaker outs are empty .
But , today I read something in 3rd power amp's site about that . They said you have to put a load to channel A's speaker out , too . I am confused so wanna ask it to the users . BTW 3rd Power Amp's stereo power amp seems to use 1 OT shared , maybe that's because of that ? :?

Secondly , if I use 2 cabs in 16 Ohms in channel B , do I have to set 8 Ohms in my power amps setting of channel B ?

Thanks in advance .

Hakan