So I have heard things about boosting different styles of brew with more sugar and/or yeast when racking to secondary. I have a cider going and I was thinking of doing just that (adding a bit more fermentable sugar). I used champagne yeast and had an OG of 1.062 and today it reads 1.000. If I do add more fermentables, how will I calculate abv%? Do I just take the new OG and FG, calculate abv% and then add the results to my current abv%?