True, but those are bright/normal channels, in Acoustic they are active/passive. So will there be volume differences?
On 140's & 270's, input #2 is padded 6dB by virtue of a higher value series resistor (22K ohms vs input #1's 10K ohms). So if you jumper out of the first channel's input #2 jack into the second channel's input #1 jack then yes you'll have to turn up the channel 2 volume control to get matched preamp drive levels, everything else being equal. But if you're going to be dialing in different tone settings then all bets are off anyway and it doesn't make much difference in the grand scheme where your two volume knobs are.
IIRC that's how I ran dual 371 stacks -- Jazz Bass to input #1 of the first 370, out of input #2 into input #1 of the second 370. Used volume controls to balance the two. Never bothered with the booster output.
