Offset Projection tool

I work in Financial Services with Financial Advice and Mortgage Broking. I assist people mainly in the debt reduction area. I need a tool that can project how to pay down mortgages quicker using a certain strategy and product. Along the time line will have event based corrections to the projection. I have attached a two pager, the first page shows 3 projections, one being a loan and its full term, the second being a loan with extra payments. The third is where I need the assistance, a projection tool that can project extra payments but specific timeline events for withdrawal. Happy to discuss further.