Well, when the level of carbon in your soil gets higher and higher it starts to lock out nitrogen..so if you can add enough quick carbon into your soil the nitrogen that is excess will be bound by the carbon, until the source of carbon ins completely broken down, and then the nitrogen that was bound will be re-released...so it is great for light cases of over fert...but don't over do the sugar, or then you get a nitrogen deficiency...I need to change my sig...it is just one of the few ways to possibly help with overfert...
I have caused a lot of overfert, and watering with sugar water is the only way I have found to help get rid of the nitro, without hurting the plant worse the way flushing does..This is the closest thing I have found so far to help....but it in no way totally clears up your mistake, but it will usually give the plant just enough time to gain the upperhand again....it is not about feeding nitrogen for me, but keeping it at bay...I don't know if the plants get it from the air or what...but I never have to use very much...and by that I mean way way way way less than recommended not nearly as often....