This article presents our experience in re-engineering a pressure sensing system - a subsystem often found in safety-critical medical devices - using the B formal method. We evaluate strengths and limitations of the B method and its supporting platform Atelier B in this context. We find that the current state-of-the-art of model-oriented formal methods and associated tool-sets, especially in automatic code generation, requires further improvement to be amenable to a wider deployment to industrial applications for model-driven engineering purposes.