We analyse the effect of interplay of the different types of inhomogeneities and the thermal fluctuation of the superconducting order parameter on the excess conductivity in a set of YBa2Cu3O7−y/Ag composite thick films. We show that the mesoscopic inhomogeneities arising due to most of the Ag residing at the grain boundaries strongly influence the tailing and the critical regions below and above the mean field transition temperature, Tc, respectively. A small fraction of Ag diffusing into the grains also produces microscopic inhomogeneities. Though these inhomogeneities are not expected to influence the SCOPF, we found that TLD, corresponding to the transition from the two to three dimensional fluctuation of the order parameter in the mean field region, as well as the inter-planar coupling strength, strongly depend on the Ag content in the composites. The effect of Ag induced inhomogeneities on the temperature window corresponding to different phases in the mean field and the critical regions are depicted in the form of a phase diagram. The large variation of TLD, and near invariance of Tc with Ag content in the films as seen in the phase diagram, are explained by invoking the role of Ag in modifying the overall electronic structure of the grains.