Is it possible to query the multiplier column from the Compounds->Calibration table of the processing method? Is it possible to use this value in *.ccf formulas?
I don't think this is possible. There was an answer to a similar question some time ago that suggested you could calculate this multplier from the Compound_Amount, Compound_Concentration and the Sample_Multipliers and Sample_DilutionFactors. In CC these are accessed using <Sample>.Multiplier(i) etc.