the complete statement to get this within one cell is:
=SUM(IF(OR(B3=1,B3=2),0%,IF(OR(B3=3,B3=4),1%,IF(OR(B3=5,B3=6,B3=7),2%,IF(OR(B3=8,B3=9,B3=10),3%,20%)))),IF(C3<=9,0%,IF(AND(C3>9,C3<=19),1%,IF(AND(C3>19,C3<=29),2%,IF(AND(C3>30,C3<=39),3%,IF(C3>39,4%,20%))))))
it works fine. Just seems so freakin messy