To properly model these regions of nuclear configuration, it is necessary to use an electronic structure method that includes state interaction so that one obtains accurate potential energy surface (PES) topologies. In order to properly account for state interaction within the MC-PDFT framework, linearized PDFT (L-PDFT) was developed whereby the Hamiltonian is expressed, in second quantization, as an operator that is a functional of the oneand two-particle reduced density matrices (RDMs). The L-PDFT Hamiltonian is generated by Taylor expanding the MC-PDFT energy expression to first order in density variables about their state-average quantities within a pre-defined model space. L-PDFT was shown to produce similar PES topologies to XMS-CASPT2 for a variety of systems, including the spiro cation. While L-PDFT, and other MS-PDFT methods, are constructed to perform well near conical intersections and locally avoided crossings, it is important that they also perform well when states are well separated. Additionally, L-PDFT has only been tested on singlet-singlet vertical excitations. In general, we hope to have a unified PDFT method which can be broadly applied to any system and any nuclear configuration, with or without close-lying states. Furthermore, as L-PDFT models state interaction via a state-averaged modification of the electronic Hamiltonian, the energies of L-PDFT differ from those of MC-PDFT even in absence of state interaction. Thus, it is important to demonstrate that L-PDFT performs as well as MC-PDFT in computing energy differences in even well-separated states.