Context: Our research is set in the industrial context of Nokia 5G and the introduction of Machine Learning Software Defect Prediction (ML SDP) to the existing quality assurance process within the company. Objective: We aim to support or undermine the profitability of the proposed ML SDP solution designed to complement the system-level black-box testing at Nokia, as cost-effectiveness is the main success criterion for further feasibility studies leading to a potential commercial introduction. Method: To evaluate the expected cost-effectiveness, we utilize one of the available cost models for software defect prediction formulated by previous studies on the subject. Second, we calculate the standard Return on Investment (ROI) and Benefit-Cost Ratio (BCR) financial ratios to demonstrate the profitability of the developed approach based on real-world, business-driven examples. Third, we build an MS Excel-based tool to automate the evaluation of similar scenarios that other researchers and practitioners can use. Results: We considered different periods of operation and varying efficiency of predictions, depending on which of the two proposed scenarios were selected (lightweight or advanced). Performed ROI and BCR calculations have shown that the implemented ML SDP can have a positive monetary impact and be cost-effective in both scenarios. Conclusions: The cost of adopting new technology is rarely analyzed and discussed in the existing scientific literature, while it is vital for many software companies worldwide. Accordingly, we bridge emerging technology (machine learning software defect prediction) with a software engineering domain (5G system-level testing) and business considerations (cost efficiency) in an industrial environment of one of the leaders in 5G wireless technology.