When you are busy, you can get lulled into a false sense of security. You feel that you are profitable.
If I see swings at this time of year, it usually means that everything isn't getting billed. There are some months where the revenues are being accounted for without the accompanying expenses. This makes the margins increase. There are some months where the expenses are accounted for and the revenues aren't, because they are in a different month. So the margins decrease.