Carbonation mistake

I have only brewed kits and partial mashes. I usually prime before bottling with 5-6 oz of table sugar for a 5 gallon batch. This has worked well with only an occasional gusher.

About a month ago I made an Irish Draught kit. I mistakenly used 2 oz of table sugar to prime 5 gallons. (I was thinking I was making humming bird nectar). Well I realized my mistake, while filling bottles, I decided to leave them in the relatively warm dining room for a few extra weeks. I tried two today and they are perfect. Nice head, lacey foam traced down the sides of the glass.

So my questions are:
Is there a large range in the amount of priming sugar?
Did I just get lucky?
Maybe is wasn’t fully fermented and there was still maltose in the beer?

Any tips are appreciated.

Thanks Brian

I’d say you have been lucky not to have bottle bombs with the other beers.

And yes, this one was probably not done fermenting for some reason.