Bottling: Adding additional priming sugar?

Brewing Processes
1

Has anyone attempted to add more priming sugar to a bottle say a few weeks after the fact? I know this can be done by cooling the bottle and adding the sugar in solution. In fact I did it by dissolving 1/4 tsp per ml for a total of 2 tsp in 8ml of water and burst heating it in the microwave to sterilize.  I then added 1 ml to each bottle.  It went fine and did not add an appreciable volume.

I’m wondering how effective it is and how long it takes to carbonate the additional sugar?  Will there be any issues going this route?

Obviously I’m doing this because I didn’t add enough to begin with due to a calculation error.

2

Never done this, the issues are obvious, too much sugar added and contamination.  Aside from this it seems like it should work.

3

I’ve done this on rare occasion.  However I used about 1/2 teaspoon of sugar per bottle.  I wonder if maybe you didn’t use enough to have any effect, since the act of popping the bottles open releases much of the existing CO2 right off the bat.