When a recipe calls for TA ( Tobacco Absolute ) it is referring to the diluted concentrate.
In other words, you take so many mls of PGA or PG, let's say 17mls. To it you add so many drops of the extract ( whatever the manufacturer's description call for ) say 12 drops and then add EM. This results in a bottle of TA that you add to your recipe per drop.
TA is the greatest thing since sliced bread. I use it in almost all of my tobacco recipes. Gives a mix that fresh cigarette smell, only in vape form that you taste.