When executed flawlessly, the finite element method (FEM) undoubtedly dominates contemporary structural analysis, providing an unrivalled approach to complex structural assessments. However, recent catastrophic structural failures in the nearby region highlight that ideal conditions are not always met. Errors made by inexperienced, careless, or inattentive software users, as well as overlooked modelling errors can lead to serious consequences. Therefore, classical methods, though less precise, but significantly more transparent, offer a valuable tool for detecting the presence of errors in modern, data-intensive analysis approaches. This paper explores further the implementation of Horne’s approximate method for determining the elastic critical loads of multi-storey plane frames. The approach still implements pure static analysis; however, it now replaces the finite element model with simplified computational models. While this approach results in some loss of accuracy, it offers a key advantage: enabling analysis solely through transparent, mainly manual calculations. Any significant deviation from FEM results thus serves as a clear indication of potential issues within the complex computational model. Furthermore, this approach also allows for the direct early detection of irregularities within individual storeys through excessive relative floor displacements, even in a simplified model. This can lead to substantial time savings before employing a more refined (still necessary) analysis model.