Do the math. What do all the 150 add up to? What do all the 160 add up to? Neither exceed 2, let alone 2.4. The dongle only goes up to 2.4 so pushing it to 2.8 would not be good and will use more resources, which could give poor decodes.
Also, if every call is being transmitted and duplicated across both sites, then you would only need one site. You would still need to keep and run the two dummy channels, but you would only start one site. Again, that would be if both sites carry the same exact traffic.
You have to trust us, even if you do not fully understand how this all works.