The following explanation is from Sheila:
After online discussion many years ago Elaine elaborated on the cheese conundrum by giving the directions that if cheese is legal if aged at least 1 month and has legal cheese ingredients that include a microbial culture ( *If a cheese is not a processed cheese (manufactured) but is a cheese that has had a bacterial culture involved with its production and is aged at least 30 days).
Cheeses that are aged at least 30 days and associated with a culture should have almost 0 carbs as the culture digests the lactose. Zero carbs equates to zero lactose. So, if a cheese has zero carbs it will have no lactose and as long as there are no other illegal ingredients added it would be SCD legal. Elaine did make the cut off 1g/ounce of cheese = 1 g of carbs/~28g of cheese.
It can sometimes be difficult to find out how long a cheese has been aged but many nutrition labels will now give you information on the amount of carbs in a serving size. From that label information you can determine if it is more or less than the legal 1 g of carbs/~28g of cheese.
And to answer your question: cheese that is aged will contain fewer carbs (lactose) than a cheese that is not aged or insufficiently aged.
Hope this helps , if not I can try to explain further.