if you add it to the secondary, its not secondary, its primary, and you'd have to rack again once it finished.
I wouldn't worry about 8 points. i'd figure out if you had lower efficiency or too much water added that caused the discrepancy, and correct it the next time you brew.
a great brewer, in my opinion, is a consistent brewer, not a person that constantly "corrects" gravities.
how many AG batches have you done? how well do you know your setup and its efficiency?
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10