Yeah I'm talking about adding an extra amount to what the recipe calls for when I'm priming on bottling day. Would this result in a more carbonated finished product ?
Yes it would, I would recommend using a carbonation calculator to achieve the desired carbonation level though. Too much and you could have some bottle bombs
Most recipes say to use more priming sugar than you need so I would hesitate to increase this blindly. I second using a priming calculator. Northern Brewer has a good one at: http://www.northernbrewer.com/priming-sugar-calculator/
I would suggest using a bottling bucket and mixing in the priming solution there. Putting the solution in the bottom and siphoning in a swirl is enough to mix it.
You DO need to add priming sugar. If you try to add the sugar to a carboy you will either, 1) not get it mixed well or 2) stir up the trub and get a lot of sediment into your bottles.