You are tasked with preparing the master budget for Microsoft Corporation for the upcoming fiscal year. The company anticipates sales revenue of $1,000,000,000, with variable costs amounting to 60% of sales. Fixed costs are projected to be $200,000,000. Develop a detailed budget plan, including sales forecasts, production budgets, and overhead costs allocation. Utilize tables to present your budgeting plan clearly, ensuring to calculate the total budgeted revenue, total variable costs, total fixed costs, and projected net income. Additionally, discuss the importance of variance analysis in budget management and how it can help identify areas of improvement.