Non-Hermitian optics combined with symmetry control offers new pathways for designing optical amplification mechanisms. Conventional parity-time (PT) symmetric systems require a precise balance between gain and loss, which is experimentally challenging to achieve. In this work, we propose a four-wave mixing (FWM) model in which the interaction between the signal and idler waves enables the realization of anti-PT symmetry, while asymmetric loss plays a crucial role in regulating energy flow and amplification. Theoretical and numerical analyses demonstrate that, in an anti-PT symmetric system, when \left| \beta^N \right| < \left| \beta_c^N \right|, the system remains in the anti-PT symmetric phase, with eigenvalues forming complex-conjugate pairs, indicating stable energy exchange and amplification. When \left| \beta^N \right| > \left| \beta_c^N \right|, the system undergoes anti-PT symmetry breaking: the real parts of the eigenvalues split, while the imaginary parts coalesce and become negative, leading to overall energy decay. Further analysis reveals that dissipation asymmetry or coupling imbalance explicitly breaks the anti-PT symmetry, causing the amplification process to be dominated by a single channel. In this regime, energy preferentially flows toward the side with lower dissipation or stronger coupling, resulting in a significant broadening of the amplification bandwidth. When the total dissipation is maintained at a moderate level, extreme dissipation asymmetry can even drive the system into a global amplification regime. Building on this framework, we introduce dual-pump modulation to investigate the cooperative effects of pump distribution and phase mismatch on anti-PT symmetry. The results indicate that an appropriate combination of pump intensity and phase mismatch substantially expands the anti-PT symmetric amplification region, thereby enhancing amplification performance, whereas large phase mismatch suppresses amplification and shifts the threshold to higher pump powers. Moreover, under symmetric pumping conditions, the product of pump intensities \left| E_p1^N E_p2^N \right| is maximized, yielding the strongest cooperative amplification. In contrast, severe pump imbalance markedly reduces the amplification efficiency, underscoring the critical role of proper pump power distribution in optimizing the performance of non-Hermitian FWM amplification. Overall, this study provides theoretical guidance for achieving stable and tunable amplification in non-Hermitian optical systems.