IFF函数有运用

假设查询表有两个字段“报告类型”、“系数”。“报告类型”下分别有FA、FB、FCS、FCF、FE、FD、DB、DC，系数的取值分别是0.005、0.005、0.005、0.0025、0.005、0.005、0.004、0.004。如何用函数自动取值，并将数值填写到“系数”列上。

iff([报告类型]="FA",0.005,IIF([报告类型]="FB",0.005,IIF([报告类型]="FCS",0.005,IIF([报告类型]="FCF",0.0025,IIF([报告类型]="FD",0.005,IIF([报告类型]="FE",0.005,IIF([报告类型]="DB",0.004,IIF([报告类型]="DC",0.004))))))))

ACC提示公式未定义，求高手指点。