In this work, discrepancies between measured single-molecule linewidth distributions and distributions simulated with the standard tunneling model in the sudden-jump approximation are studied for terrylene and di-tert-butyltenylene dopant molecules in poly(vinylbutyral). The experimental data has been carefully checked for systematic errors. It is shown that the results are in disagreement with the standard model, but that the incorporation of a distribution of molecule-polymer coupling strengths would remove this disagreement. Additionally, the experimental observation of a surprising correlation between the single-molecule line areas and the matrix-molecule interaction strength is presented, and a hypothesis is put forward for its physical origin.