Ah, right. The guide assumes that you will have Broadcasting Mode start OFF in all windows, and for Diablo 3 you're having it start ON.
The Repeater Target that will be active when you first launch your team is configured in your Repeater Profile, and defaults to "all other" (Window: All w/o Current). Until you use the Shift+Alt+R toggle, this default Repeater Target is active. I don't necessarily recommend changing it there (you certainly can) but be aware that this is the default setting.
Secondly this is the part that sets who the broadcasts to in what you described:
|-----> Repeater Target 'all other' -> Isboxer&~dxnothing
This is saying that for every isboxer window except dxnothing (if you're using it; most people don't), the Repeater Target (where broadcasts should go to from that window) should be "all other" (Window: All w/o Current). That's what you want to adjust.
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New suggestion:
The Mapped Key Wizard has a "Broadcasting Toggler" option that the howto should actually be updated to use. In the Wizards menu, select Mapped Key Wizard. Pick a Key Map to put the toggle in; probably "Always On" but make sure you pick a Hotkey you're not going to need for some other reason (like typing in the chat window for example, so you don't want your hotkey to be Enter...). After picking the Key Map, it will ask you what type of mapped key to set up, pick "Broadcasting Toggler". Then you get to fill in the details of how your toggle should work; Name it, Hotkey it, check the "This toggle should turn broadcasting OFF instead of ON" box (since your broadcasting mode starts on), and choose from the FROM/TO boxes.