Abstract Quantifying energetic electron precipitation is essential for understanding ring current and radiation belt loss, as well as magnetosphere‐ionosphere‐atmosphere coupling. The count rate ratio between the 90° and 0° telescopes (CR90/CR0) on POES/MetOp satellites is a commonly used proxy for precipitation and pitch‐angle diffusion rates (DW ${D}{W}$). Traditional interpretations assume nominal detector fields‐of‐view and neglect azimuthal drift. Using a comprehensive Drift‐Diffusion model, we quantify for the first time the combined effects of realistic detector angular responses, including significant out‐of‐field contributions, and azimuthal drift on the CR90/CR0 versus DW ${D}{W}$ relationship. Realistic responses cause this relationship to flatten as diffusion weakens, while azimuthal drift increases the CR90/CR0 ratio, creating significant longitudinal and hemispheric dependencies. Neglecting these combined effects during slow diffusion leads to substantial overestimation of DW ${D}{W}$ and precipitation flux, resulting in significantly overestimated ionospheric ionization rates. This study provides a more accurate framework for resolving DW ${D}{W}$ and electron precipitation using low‐altitude satellite data.