We report photomodulated reflectance measurements of several intersubband transitions for a series of as-grown InyGa12yAs12xNx /GaAs multiple quantum well samples as functions of hydrostatic pressure ~at room temperature! and temperature ~at ambient pressure!. The experimental results provide support for the effects of disorder due to different nearest-neighbor N-cation configurations. The quantum well transition energies obtained from the photomodulated reflectance spectra are fitted as a function of pressure with a realistic 10 band k•p Hamiltonian, that includes tight-binding-based energies and coupling parameters for the N levels. The quality of match between theory and experiment confirms the theoretical model and predicts some important material parameters for dilute-N InGaAsN alloys.