I need an Excel expert to add a VAT (5%) feature to my existing Excel-based accounting and inventory software. Requirements: - Apply VAT on multiple sheets - Update totals while keeping existing functions intact - Display VAT on each relevant line item and in a summary section Ideal Skills: - Proficiency in Excel (2013 to 2019) - Experience with multi-sheet workbooks - Attention to detail and accuracy Please ensure the current functionality remains unchanged after the update.