The dependence of JET neutron deficit and energy balance on neutral beam (PINI) selection has been investigated experimentally. The discrepancy between neutrons predicted and measured during JET pulses has consistently deviated, with the measured neutrons typically being lower than expected by simulation. A number of investigations into this have been carried out, e.g. [1]. Further to this the energy balance on JET has shown a discrepancy of ~25% [2]. The neutron production on JET is split between thermal fusion reactions and beam-target reactions, with beam-target reactions dominating in deuterium-deuterium discharges. Given this dominance of beam-target reactions and the importance of NBI heating to JET plasmas it is important to have a good understanding of the behaviour of JET NBI in the plasma including a good understanding of the NBI power calibration. To improve this understanding a series of experiments were carried out involving a single PINI at a time into a stable, L-mode plasma. These pulses were then analysed using the TRANSP code to determine how the predicted & measured neutrons varied with PINI selection. To further aid the analysis charge exchange beam spectroscopy was also carried out. The variation of neutron deficit with PINI selection will be shown, with larger deficits seen on those PINIs that are more off-axis. Where possible a comparison between the same PINI positions on different beamlines will be shown to separate technical and physics causes of a deficit. The details of the method used for NBI power calibration and error analysis will also be shown.