Light extinction coefficient

Hi, I am trying to use my extinction coefficient field data (converted from Transmissometer readings) through a dynamic light extinction coefficient file. The filed data refers to the total extinction coefficient (Lambda) including the EH2O and EXOM, but the example of the light extinction file from the user manual (page 692) shows that the file is exclusively used for the ExH2O. I have set all the extinction coefficients to zero in the control file and have turned EXC and EXIC on. Which basically, means that I assumed the filed extinction coefficients are only due to the EXH2O (pure water). 1- Is this going to make a problem? (field extinction coefficients range from 0.1 to 16 for Zone2 Pit Lake) 2- Even though I am using dynamic extinction coeffs, the pre-processor gives me an error (Pure water light extinction < 0.25 for waterbody 1) since I have set the EXH2O to zero in W2 control. However, the w2_3.7_64.exe runs the model without any error. Should I care about this error from pre.err? Thanks,