In this work, we demonstrate how an adequate selection of hologram generation methods can lead to improved phase-only multiplexing. In particular, we show that the multiplexing of phase-only holograms is not a phase-only function, which means that amplitude truncation is required after multiplexing for applications involving phase-only modulation. This truncation produces a loss of quality. We demonstrate that this loss depends on the method used to generate the individual holograms to be multiplexed. Additionally, we evaluate the phase multiplexing performance of three iterative and non-iterative hologram generation methods, namely the one-step phase retrieval (OSPR), the iterative Fresnel algorithm (IFrTA), and the optimized Fresnel random phase (OFRAP). We make use of entropy metrics to analyze the amplitude obtained after multiplexing the phase holograms generated with these methods. To show the possible applications of our analysis for the generation of 3D scenes, the multiplexing is performed for two cases: in the first, all holograms have the same reconstruction plane, and in the second, the multiplexed holograms have different reconstruction planes. Our results show that the reconstruction obtained by multiplexing holograms generated with the IFrTA is more affected by the loss of amplitude information than the OFRAP result. In this way, we demonstrate that the use of OFRAP leads to better phase-only multiplexing performance compared to IFRTA or OSPR. To support our conclusions, we perform numerical reconstructions and corroborate these results with experimental reconstructions achieved with a phase-only SLM.