One MPK225 + Two FL Synths = How Switch Between Them?

[Norrec]

I've got a MPK225 and two Synths in FL Studio. I want to switch which MIDI channel the MPK225 outputs on so that I can switch synths without having to click on one with my mouse.

1) Under the MIDI settings I set the MPK225 to 'Enabled' but have left the 'Port' unassigned. The idea here is I will control the MIDI output from the MPK225 itself. I know from experimentation that 'MPK225' equates to 'USB A1 - A16' on the controller itself. 'MIDIIN2 (MPK225)' equates to 'USB B1 - B16' on the controller. In this way I could accomplish what I want by assigning MPK225 = Port 1 and MIDIN2 (MPK225) = Port 2 but I would only ever be able to control two instruments. I should be able to control 32 instruments.

2) On the instruments I set one to 'Input Port = 1' an the other to 'Input Port = 2'

3) On the MPK225 I press 'Edit' and press a key. The display changes to 'Keyboard' and I change 'MIDIChannel' to USB A1. I hear Synth1! I change MIDIChannel to USB A2 and I still hear Synth1. This doesn't appear to be changing anything. If I keep going and get to USB B1 sound stops. This is how I learned what 'MIDIIN2 (MPK225)'.

It doesn't seem like what MIDIChannel I pick does anything. Only USB A# or USB B# does. Is that just how it is and I'm misunderstanding? What then is the purpose of having 16 values if only the letter is used? It's starting to feel like I can only control two instruments at once (A/B). Maybe the Keyboard is special and the 1-16 refers to the pads/knobs?

[NTO]

From MPK manual, I get the impression you will ...

[Norrec]

Thanks NTO, that's what I needed. I didn't kno...