Exactly.
You don't count the DH crowd toward the aggregate twice. The aggregate is exactly that - the aggregated number of people who attended in that round. This round, that will consist of four crowd figures.
What it comes down to is how they want to average it, which is where the sticking point came last year, as they didn't use a consistent method.
Personally I think the average figure should be round aggregate divided by games played, but I can see this weekend we may end up with it being divided by four instead, averaging the "events" rather than the "matches".