UR44 Rev-X Send Selection

In the UR44 Operation Manual, at page 33, there is a block diagram showing that, apparently, you can select whether sending the Rev-X reverb to Mix1 or Mix2 busses.
It apparently should be selected by the blue button SEND on the dspMixFx interface
Anyway, it seems not having any effect: if I record with a microphone and add some reverb, I can hear it on both Mix1 and Mix2 busses (for instance plugging earphones on Phones1 and Phones2 output anr routing Phones2 to Mix2), whenever I activate SEND on Mix1 or Mix2.

At page 35 of the same manual there is a more complete shematic of the UR44 signal routing.

Here I can understand that the sketched REV pots are the blue ones in dspMixFx placed under each channel, to decide how much signal has to be sent to the REVERB bus, the LEVEL pots are the orange ones (one for Mix1 and one for Mix2, independent) which allow selecting how much from the REVERB bus must be routed to Mix1 and Mix2 busses.
But on the diagram there are also some SELECT buttons (one for each channel), which should allow enabling or disabling channels independently from sending the signal to the REVERB bus. These buttons cannot be the blue SEND one on the dspMixFx because they have no selection between Mix1 and Mix2 and on the interface there should be one on each channel.

So, in my opinion there is some mismatch between the documentation, the UR44 HW implementation and the dspMixFx interface.
Playing on the blue and orange pots on dspMixFx it is still possible to route the reverb from each input to each bus, but the SELECT button on the Manual does not exist in the HW and the SEND blue button on the dspMixFx interface seems having no effect.

Do you agree or I’m missing something?
Thank you!