Move Our Cash-Planning Portal to a Maintainable Stack

Our cash-planning portal has outgrown its original framework. Calculation logic is sound, but the interface is difficult to extend, financial guidance lives in scattered templates, and each release creates avoidable regression risk. The goal is a staged migration that preserves customer data and calculation behavior while giving our team a cleaner foundation. Initial deliverables are an architecture and content audit, a migration sequence, rebuilt high-use account and forecasting flows, parity tests for calculations, revised in-product explanations, and deployment documentation. After the core move, we would like an ongoing monthly arrangement for maintenance and incremental improvements. We can structure the initial 5,500-level engagement with part of the payment deferred to agreed migration and stability milestones. Please propose a schedule that protects both sides and makes acceptance conditions unambiguous.