The study of different objects such as: properties of algebraic structures, analysis of chemical graph structures without experiment or understanding networks through topological indices (TIs) is among modern directions in graph theory. The analysis of different networks such as benes network, butterfly network, Hex-derived network and biswapped network by using TIs is one of the modern research fields. The storage and transferring of the data carrying certain information has always remained a modern world problem. The optoelectronic technology used in optical transpose interconnection systems (OTIS) is efficient in outcome over an electrical system due to minimum power consumption and broad bandwidth. By combining the use of wireless and electrical technologies, OTIS has developed into a valuable network and boosted the efficiency of contemporary optoelectronic computers. A special type of OTIS is based on the biswapped network over path graph Pn, denoted by B(Pn). In this research work, a maximal twin-preserving subgraph of a biswapped network over path graph Pn is constructed. Moreover, the biswapped network B(Pn) and its constructed subgraph are explored through ev-degree and the ve-degree dependent TIs. A comparative analysis of the ev-degree and the ve-degree dependent TIs for B(Pn) and MT (B(Pn)) (a twin-preserving spanning subgraph of B(Pn)) is among the principal findings of present work. The analytical formulae, table and the graphical trends are used to describe a comparison between the TIs of the B(Pn) and its maximal twin-preserving subgraph. It is shown that the values of TIs only differ by a constant and does not depend on the value of n. Besides this, to analyse the complexity of MT (B(Pn)) through information functional based entropies, we define ve-degree and ev-degree based information functionals and compute formulae for ve-degree and ev-degree based entropies using information functionals. Numeric tables and graphs are also used to study complexity of MT (B(Pn)).