The insertion point is the default location products will be added into the project spreadsheet.
By default, the insertion point is set to LAST. This makes all items added to the spreadsheet go to the bottom and continuing the number sequence 1,2,3 etc.
At any time you can change the insertion point to add a product anywhere on your spreadsheet. The selections are Insert Above Current Line, Insert Below Current Line and Insert as Last Item.
This can be very useful on bigger projects where you may need to replace or insert a product in a specific location on a spreadsheet.