Oxygen into the beer during dry hopping has some effects on the final aroma I have found, Try to add the hops when there is still some fermentation to go, like when your 5 points from FG. The reason for that is so that you get co2 produced that scrubs out the oxygen from when you opened the FV.
The tricky part is that adding hops when fermentation is still going means a lot of volatile oils get taken up by the yeast due to its stickiness. I tend to add 1/3 of my hops at the end of fermentation and after 2-3days add the rest, this gets great aroma.
If I had a better FV I could flush it after dry hopping with co2 which is what some pro's brewerys do, possibly some Home brewers as well.
Edit ; and one other thing is.....less is sometimes more. I've dry hopped with 100g of Simcoe and got low aroma, used a combo of Simcoe, Citra and galaxy at 14g each and the aroma was solid......also to mention is my dry hopping goes for 5-10days, depending on which hop is used.