A fund manage would look at a basket of SP500 stocks (as an example), he would sell one stock at loss, and at the same time buy another similar stock to avoid wash sale. If he controls the entire portfolio, he can make sure you dont end up buying and selling the same stock within 30 days
But if you also trade, you could buy or sell the same stock he is doing
This is just one example. You should ask your advisor what is his exact strategy for harvest loss