Scala, a cousin of Java, is a hybrid language that blends Object-Oriented Programming (OOP) and Functional Programming (FP) features seamlessly. As programming languages evolve to support multiple paradigms, assessing code quality becomes increasingly complicated. Traditional OOP metrics and existing FP complexity measures are often falling short in capturing the quality impact of multi-paradigm code. Even previous work on multi-paradigm metrics did not take into account the interplay of mixed-paradigm usage within a single language. In this paper, we presented and evaluated a set of maintainability metrics to measure the degree of mixed-paradigm usage in Scala by extending a previously existing analysis framework. Results from an empirical study on 10 matured open-source Scala projects indicate that metrics related to paradigm switching and the stretch of each switch are potential indicators. These metrics can be incorporated into existing maintainability assessments alongside traditional metrics to provide a more comprehensive view of code quality in industrial mixed-paradigm environments.