It usually applies to utilization but could apply to aroma additions. If your beers are coming out the way you like them, don't change anything.
Altitude additions are to compensate for two things: Slightly lower utilization and loss of taste sensation at altitude.
The latter is highly debatable, IMO, because loss of smell is somewhat temporary. A person plunked down at 7800 ft (or taken into an airplane) will have a reduced sense of smell for a while. Apparently after a week or two, the body acclimates and all is well.
Lower utilization is simply due to the lower boil temperature at altitude vs sea level. There again, the length of a boil can compensate for this. Truly, 5% may well be below the threshold of taste or within an acceptable margin of error from hop aging. It depends on the beer.
I brew at sea level, but I know a lot of brewers at high altitudes. The subject of compensating for altitude in ingredients doesn't come up. More often it's boil times and DMS.