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Your right. The documentation does show units of percent. Same for the next field of drift loss percent. A review of the code shows that the Evaporation Loss Factor field is currently a fraction, not percent, of water flow rate.

The IDD shows the same information described in the Input Output Reference document:

N19, \field Evaporation Loss Factor
   \type real
   \units percent/K
   \note Rate of water evaporation from the cooling tower and lost to the outdoor air [%/K]
   \note Evaporation loss is calculated as percentage of the circulating condenser water rate
   \note Value entered here is percent-per-degree K of temperature drop in the condenser water
   \note Typical values are from 0.15 to 0.27 [%/K].
   \default 0.2
N20, \field Drift Loss Percent
   \type real
   \default 0.008
   \units percent
   \note Rate of drift loss as a percentage of circulating condenser water flow rate
   \note Typical values are between 0.002 and 0.2% The default value is 0.008%

And the code where these data are read in shows:

SimpleTower( TowerNum ).UserEvapLossFactor = NumArray( 19 ); //  N11 , \field Evaporation Loss Factor
SimpleTower( TowerNum ).DriftLossFraction = NumArray( 20 ) / 100.0; //  N12, \field Drift Loss Percent