To sustainably live on and explore the lunar and other planetary surfaces, in situ regolith will need to be used for resource extraction and infrastructure development. To evaluate and ensure such safety and efficiency of excavation operations in variable, site-specific regolith terranes with given equipment designs, reliable computational models are necessary. The work here evaluates the accuracy and reliability of a standard, well-established excavation force prediction model using published data from a previous planetary excavation experimental study and establishes efficiency metrics for force reduced excavation as a proof-of-concept. It is shown that the established excavation force prediction model is not able to simulate planetary excavation mechanics sufficiently and hence more advanced models of lunar and planetary excavation are needed to enable safer, faster, and more economical resource acquisition hardware development. The case study of the efficiency metrics being applied to the published data shows informative trends that can be used in future excavation hardware and tool path optimizations. These are recommended for use in future planetary excavation modeling and planning workflows.