A new version of Excel Spreadsheet using formula
1. Use "Parameter" tab to maintain product category and capacity; 2. Use "Product" tab to maintain each product's properties: product name, category, unit cost, special unit cost, capacity; 3. With "Price" tab: - Cost Price and Special Price are calculated by input quantity * looked up unit cost / unit special cost from "Product" tab - Subtotal of Installation Costs: Installation Unit Cost * sumed up quantities for those products having capacity "20-35 Kw" / "46-95 Kw" (using sumif formula). Feel free to contact me for more details if you're intested in my solution.