Had me a bit confused on this one for a second. I don't remeber anyone mentioning the increase in the SG after adding the F pac, but obviously it is going to increase, but wont ferment.
Because the sorbate was added this wine is no longer fermentable. Right? Well, I know its right. It also makes sense that once the f pac is added the SG will increase because of the sugars, but will not and can not ferment.
As obvious as this sounds, I could see how you would think something was odd when you go from below 1.000 to back up to 1.020.
"Never let a seal lick your finger after you have been handling fish, because, afterall, a seal is going to be a seal" -Eskimo Proverb