How do I restore the quantity field to invoices (so that customers can see how many of something they're getting for the amount they're paying per line item?

I run a service business, and billing is hourly. If someone is charged a $200 hourly and the quanity is .5 for that line item, the line item should read $100. That was all fine with the desktop product, and even here online for a while. Today the quantity field disappeared, so that just the date, service, and amount with no quantity or per unit (hourly) specified, so the customer can't tell for how much time they're being charged. I tried different invoice templates, it doesn't seem to let me create new ones, I've tried turning on every option in Design or Customization of the invoice. None of that works? Where did "Quantity" go, and how do I get it back? THANKS!