correct.
Whenever connecting a Quad to a switch, you must use 1 of the pairs of outputs. Either ports 1 & 2 or 3 & 4. The DP-34 manual even mentions this point.
The reason is, because prior to a switch test being performed and activating the built in switch, the outputs are as follow:
Output 1 - 119
Output 2 - 110
Output 3 - 119
Output 4 - 110
When the outputs are sent to a switch, the switch only uses the default satellite from the output, not both, since it does it's own switching.
Therefore to have both satellites at the switch, you need a pair. 1 & 2 or 3 & 4. Of course 1 & 4 or 2 & 3 could possibly work, but I don't think I've ever seen them used like that.