An improved movement-based registration scheme [2] reduces location update cost on conventional movement-based location update scheme [1] but increases uncertainty of the position of a mobile terminal (MT). The effect of this uncertainty of the MT position on the paging cost of the improved movement-based registration scheme is analyzed. We show that the paging cost of the improved movement-based registration scheme in [2] is underestimated, especially for large values of movement threshold. The result shows that the underestimation cannot be ignored.