A functional fluid composition comprising: greater than 50 wt.% of a base oil, based on a total weight of the functional fluid composition; an additive composition prepared by mixing: a) a hydrocarbyl acid phosphate of the formula in an amount sufficient to provide at least 50 ppmw to 500 ppmw of phosphorus to the functional fluid composition, based on the total weight of the functional fluid composition: wherein R is a linear or branched hydrocarbyl group having 1 to 6 carbon atoms and R 1 is selected from hydrogen and a linear or branched hydrocarbyl group having 1 to 6 carbon atoms; b) an amount of one or more calcium-containing detergent(s) sufficient to provide at least 25 ppmw calcium to up to 800 ppmw calcium to the functional fluid composition, based on the total weight of the functional fluid composition; and c) one or more nitrogen containing dispersants in an amount sufficient to provide greater than 20-1200 ppmw of nitrogen to the functional fluid composition, based on the total weight of the functional fluid composition; and wherein the functional fluid composition has an electrical conductivity of 80,000 pS/m to 180,000 pS/m, as determined by the method of ASTM D2624-15 with a digital conductivity meter from EMCEE Electronics, at 170°C having a conductivity range of 1 - 200,000 pS/m. greater than 50 wt.% of a base oil, based on a total weight of the functional fluid composition; an additive composition prepared by mixing: a) a hydrocarbyl acid phosphate of the formula in an amount sufficient to provide at least 50 ppmw to 500 ppmw of phosphorus to the functional fluid composition, based on the total weight of the functional fluid composition: wherein R is a linear or branched hydrocarbyl group having 1 to 6 carbon atoms and R 1 is selected from hydrogen and a linear or branched hydrocarbyl group having 1 to 6 carbon atoms; b) an amount of one or more calcium-containing detergent(s) sufficient to provide at least 25 ppmw calcium to up to 800 ppmw calcium to the functional fluid composition, based on the total weight of the functional fluid composition; and c) one or more nitrogen containing dispersants in an amount sufficient to provide greater than 20-1200 ppmw of nitrogen to the functional fluid composition, based on the total weight of the functional fluid composition; and a) a hydrocarbyl acid phosphate of the formula in an amount sufficient to provide at least 50 ppmw to 500 ppmw of phosphorus to the functional fluid composition, based on the total weight of the functional fluid composition: wherein R is a linear or branched hydrocarbyl group having 1 to 6 carbon atoms and R 1 is selected from hydrogen and a linear or branched hydrocarbyl group having 1 to 6 carbon atoms; b) an amount of one or more calcium-containing detergent(s) sufficient to provide at least 25 ppmw calcium to up to 800 ppmw calcium to the functional fluid composition, based on the total weight of the functional fluid composition; and c) one or more nitrogen containing dispersants in an amount sufficient to provide greater than 20-1200 ppmw of nitrogen to the functional fluid composition, based on the total weight of the functional fluid composition; and wherein the functional fluid composition has an electrical conductivity of 80,000 pS/m to 180,000 pS/m, as determined by the method of ASTM D2624-15 with a digital conductivity meter from EMCEE Electronics, at 170°C having a conductivity range of 1 - 200,000 pS/m.