Where disablement is liable to fluctuation the rate of pension is necessarily subject to periodic reassessment up or down according to any change in the average degree of disablement found on medical examination. Reassessment is not made without such examination, and no pension is reduced or cancelled where the disablement resulting from war service remains the same. On re-survey medical boards are required to consider equally the question whether there has been worsening due to war service or improvement in the accepted condition.