ok ray ray try looking at it like this
b.c , rd avg 70 pf 74 p against
b.c , con avg 73 pf 70 p against
b.c avg pf 71.5 p against 72
gt home avg 83 pf p against 63
gt con avg 73 pf p against 73
gt avg pf 78 p against 68
so when u crunch one more time , for instance
when u take bc 71.5 pf avg with gt p against 68 gives u 70, so when u take the 78 of gt and combine it with p against 72 =75
75-70 gt, total of 145 should get ya close, hope this helps