超出部分用公式
=IF(B2-A2>20000,(B2-A2)*15%,IF(B2-A2>10000,(B2-A2)*10%,(B2-A2)*5%))
假设完成数在A1，用公式：=SUMPRODUCT(TEXT(A1-{0,10000,20000},"0;\0")*{0.05,0.05,0.05})简化为：=SUMPRODUCT(TEXT(A1-{0,10000,20000},"0;\0")*0.05)
