1. Remove Description header above every section.
2. Remove Unit & Qty headers by having the Unit come right after the Qty.
3. Remove Unit Price by putting an "X" (times symbol) before the unit price and after the Unit & Qty (don't allow unit price without the Unit & Qty)
4. Remove Line Total by making it bold
5. Make the section titles a different size or shaded background, anything to separate it from a regular line item. You could even put a simple box around the line items below each section title, with the section title directly above the box

With each section's line items outlined with the title above and no section titles, the page will look so much cleaner and easier to read. I made a rough example of what I meant attached here, the red being the suggested added changes along with the erased headers. It also shows how it might look if the section line items for a single section continued to another page.