Late hop additions are more than the last 5 minutes. That would be an aroma addition. I've done late additions of as much as 25 minutes,adding hops every 8 minutes,30 seconds with 4,5oz of 3 different hops in my IPA. One being "whole leaf". Not really whole..seem to be cut up. I've noticed LD Carlson calls them whole leaf,whereas Hop Union calls them raw hops. Same cut up look,but I noticed today while adding them to a Burton ale that there were still some whole cones in there.
And boy do they soak up liquid! Had to pour the wort with loose hops in it through my fine mesh strainer to get them separated with the little bit of cold break material. Squeezed them with my paddle to get more liquid back. Angels share my foot...I want my beer back. lolz. Pellets do seem to not soak up quite as much,but whole leaf seems to give better flavor. Pellets may give better bittering,ime.
Dry hopping is done either in primary after FG is reached,or secondary at that same time. I use muslin bags,but small paint strainer bags would be ok. The pellets disintegrate into this grainy mass of pulp. 1oz of pellets per hop sack,use a grain bag for 1oz of whole leaf,as they swell to a larger mass. Dry hop for 7 to 10 days. Any more time,& you can start getting grassy flavors.