Eplained why there is only one DUT in the tb.

libraries/base/common/tb/vhdl/tb_common_adder_tree.vhd

@@ -169,6 +169,8 @@ BEGIN
     out_dat => result_expected
   );
   
+  -- Using work.common_adder_tree(recursive) will only invoke the recursive architecture once, because the next recursive level will default to using the last compiled architecture
+  -- Therefore only instatiatiate the DUT once in this tb and use compile order to influence which architecture is used.
   dut : ENTITY work.common_adder_tree  -- uses last compile architecture
   GENERIC MAP (
     g_representation => g_representation,