J. Albrecht`s Function Point Analysis (FPA) is a method to determine the functional size of software products. An organization called International Function Point Users Group (IPFUG), considers the FPA as a standard in the software functional size measurement. The Albrechts method is followed by IPFUG method which includes some modifications in order to improve it. A limitation of the method refers to the fact that FPA is not sensitive enough to differentiate the functional size in small enhancements. That affects the productivity analysis, where the software product functional size is required. To provide more power to the functional size measurement, A. Abran, M. Maya and H. Nguyeckim have proposed some modifications to improve it. The IPFUG v 4.1 method which includes these modifications is named IFPUG v 4.1 extended. In this work we set the conditions to delimiting granular from non granular functions and we calculate the static calibration and sensitivity graphs for the measurements of a set of projects with a high percentage of granular functions, all of then measured with the IFPUG v 4.1 method and the IFPUG v 4.1 extended. Finally, we introduce a statistic analysis in order to determine whether significant differences exist between both methods or not.