         # The smallest value precision that captures at least
         # one non-zero digit for all non-zero values.
         precision = Chart.minPrecision(values)
-        # The value formatter shows three decimals more than
-        # the minimum.
-        valueFormatter = d3.format(".#{ precision + 3 }f")
         # The tooltip content generator.
-        generateTooltip = tooltipGenerator(paramKey)
+        generateTooltip = tooltipGenerator(paramKey, precision)
         # The tooltip and Y tick formatter depend on the precision.
         mixin =
           options:

          singleParameterConfiguration(modelingResults, paramKey)

      # @param paramKey the modeling parameter key
      # @returns the tooltip HTML content generator function
      tooltipGenerator = (paramKey) ->
         # The tooltip value heading.
         if paramKey is 'kTrans'
           propertyFormatter = (modelingResult, property) ->
             dspConf = Modeling.properties[property]
             # The value to display.

               "<td>#{ dspConf.html }:</td>" +
               "<td>#{ valueFormatter(value) }</td>" +
             "</tr>"
           
           # Return the formatter function.
           (obj) ->
             # The charting object is the data series object,
             # for either the FXL or FXR ktrans. In either case,
             # the modeling parameter result is in obj.data,
