In our present study, we consider surface-CO coverages reflective of experimental conditions, where coverage θ can range from 0.17 to 0.5, depending on the study. This can necessarily alter the site geometries of CO molecules with a low coverage which consists primarily atop CO sites, and coverages of 0.33-0.5, which achieve mixtures of atop, bridge, and hollow-site CO. Nekrylova et. al.'s vibrational and thermal desorption spectroscopic study of CO on Pt (111) at 20 K found that the hollow-site CO's infrared (IR) band of 1736 cm -1 appeared at θ = 0.35 and increased in intensity as the coverage reached θ = 1.0. With the advent of in-situ scanning tunneling microscopy (STM), the ratio and position of atomic, bridging, and hollow sites can be precisely identified, highlighting the importance of CO-CO lateral interactions. Moreover, while both in-situ STM and IR-absorption spectroscopy (IRAS) can agree on the appearance of different sites at specific coverages, the ratio of the different kinds of occupied sites can vary considerably as demonstrated in a study of CO on Pt (111) by Villegas, et. al. At θ = 0.75, STM images found a ratio of atomic:hollow site occupation of 1:2 per unit cell, while integration of corresponding IRAS data yielded 2:1. Since STM is likely the more reliable measure, the discrepancy between these experiments warrants some caution in inferring coverage from IR data. The difference between the two experiments was attributed to the dynamic dipole coupling effects related to CO-CO interactions, but it also suggests that there can be some ambiguity to the exact occupation of specific sites when analyzing IRAS data. Moreover, the richness of the experimental data indicates that theoretical models should take into account information about the coverage and distribution of sites in the actual experimental samples. We consider atomic, bridging, and fcc hollow CO sites at θ = ¼ coverage, and combinations of them which correspond to experiments at θ = ½ coverage. This allowed our theoretical model to closely match the coverages present during the experimental conditions of different photoemission studies. In this work, we elucidate how QSGW's ability to match photoemission data with high fidelity, and make it possible to resolve the unique features related to different CO site occupations.