In the past decade and half since their introduction, multiple frameworks of mechanistic models were made available to enable the quantification of loss of lithium inventory and loss of active materials. They usually come either with capacity/state of charge-or lithiation-based matching for the electrodes. While both approaches were believed to be equivalent, the present work will show that they are not when used with materials that are not fully delithiated at end-of-charge because they differ on how they account for inaccessible lithium. Herein, we will explain these discrepancies and propose new equations to improve both types of frameworks.