Late extract additions are great for lighter color,& cleaner flavor. In other words,no cooked extract "twang". LME is more prone to darkening in the boil than DME. So,for example,if I'm using a cooper's can,I'll add that at flame out. Since the wort is still boiling hot,& pasteurization happens about 162F,covering & steeping a few minutes gets the job done.
You can buy,say, a 3lb bag of plain (read un-hopped) light DME & use half (1.5lbs) in a 2.5-3.5 gallon boil for some hop additions. Then at the end of the boil (flame out) stir in completely the remaining DME & the cooper's can. Or Munton's can,for that matter. See my recipes under my avatar for detailed examples.