christmas ale flavor change

i brewed a 10 gallon batch of christmas ale last month and i kegged it. out of the secondary it had a strong chocolate smell and taste, i wanted the ginger and cinnamon to be more potent. when i first tried it out of the keg when it was carbonated, it tasted amazing and had the flavor that i was looking for from the ginger and cinnamon. 4 days later those tastes were gone. i'm wondering if i can add more of the spices to the keg and get them back. should i add the same amount that i added to the boil, or just add a little and see if i like it and continue to add more until the desired taste is acquired? just don't want to mess up the beer.