Canada Worker's Comp - What is WC Premium calculation for AB 700010000?

Hello,

Three questions on Canada Worker's Compensation that I am hoping you can educate me on:

1. What is the Worker's compensation premium calculation for an EE with TARA/TARR 700010000? Is it the below calculation correct? if not, what is missing or wrong?

    

     Gross Wages for pay period                                                       $6,406.25      .....................Gross amount on R773601 / agrees to F06156                                                                    

     add Taxable Benefits - i.e. auto use,Life 2X, ADD 2X                   +  227.00      ...................Benefit Amount on R773601 / agrees to F0627 & these are in F06156

     Taxable Gross Wages                                                                  $6,633.25

     less Excludable Amount                                                               - 2,520.75        ............. ?? what are examples of this?? I cannot tie this out! 

     WC Adjusted Gross Wages                                                          $4,112.50   .......................Reportable amount on R773601 / agrees to F0627 (source)