Questions about "Material model/latent heat melt": input parameter"reference temperature" is useless?

ASPECT
1

Hi,
As the title, I find the change of “input paameter:reference temperature” doesn’t influence the density profile in my model, it’s like that the value of “reference temperature” always be zero in the input.
Then I read the “source/material model/latent heat melt.cc”, the code as follows:

const double delta_temp = in.temperature[i] - reference_temperature;
........

 if (this->include_adiabatic_heating ())
    {
       // temperature dependence is 1 - alpha * (T - T(adiabatic))
      temperature_dependence -= (in.temperature[i] -this>get_adiabatic_conditions().temperature(in.position[i])) * thermal_alpha;
     }
    else
       {
         temperature_dependence -= in.temperature[i] * thermal_alpha;
       }
.............

out.densities[i] = (reference_rho + composition_dependence + pressure_dependence)*
temperature_dependence * (1.0 - melt_dependence);

density=reference_density*(1 - alphadeltT) ;
but the code was written as density=reference_density(1 - alpha*T). i.e. " temperature_dependence -= delt_temp(not in.temperature[i]) * thermal_alpha