You're tasked with selecting an appropriate interest rate for a construction project. This rate will be crucial for financial assessments involving two construction methodologies. Your goal is to determine the preferred methodology based on Breakeven Analysis, Return on Investment $($ROI$),$ and Net Present Value $($NPV$)$ calculations.

Two Options for Construction Methodologies:

Option $1$: Traditional Construction Approach

Initial Costs: $$300,000$ for raw materials and equipment in the first year; $$50,000$ for customization and additional labor costs. There will be an ongoing annual maintenance cost of $$30,000$ for the project's duration.

Expected Outcome: A reduction in labor expenses by $$40,000$ per year due to increased efficiency in construction processes.

Option $2$: Modern Prefabrication Method

Initial Costs: $$400,000$ for prefabricated materials, assembly, and specialized equipment spread over the first two years. Maintenance expenses are expected to be $$60,000$ annually for the first three years.

Expected Outcome: A decrease in construction time leading to a reduced labor requirement, resulting in $$20,000$ savings per year.

Both options anticipate an increase in project scale by $15\%$ annually, starting from the current $$2$ million project value.

Assuming a five$-$year project duration, select an interest rate to proceed with your calculations and then determine the recommended construction methodology based on the Total Cost of Ownership $($TCO$)$ for each option.

Remember to consider the projected increase in project scale when assessing the financial viability of each methodology.