The Economy tab of the Govern window lists United Planets Taxes as one of the items under Weekly Expenses. However this value always is zero (at least in the 2 games I've done so far). While in the United Planets tab of the Diplomacy window, it lists the costs of each resolution, and totals the UP taxes at the bottom. In my current game this is 4bc, not the 0 shown in the Weekly Expenses.
The Economy tab with Weekly Expenses:
The United Planets tab:
