Disregard empty cells

The attached sheet shows a league table for a simple competition run over 20 or so weeks for 12 teams and with a quirky scoring system. The problem I have is recording the total number of tied games accumulated by the teams (tied games being worth one league point). Having laid out the fixtures for the entire season the formula at cell H4:M4 effectively counts the empty cells in columns C&D for future games as being tied by virtue of null value equaling null value or whatever. Yes I could write or copy and paste the fixtures but having come this far..... What can I add/create to solve the empty cell problem? TIA