Is there any advantage to selling an Iron Condor over selling the Call and Put Vertical Spreads that make up the Iron Condor. In TOS I can not figure out how to adjust one side of the Iron Condor when I sell it as one unit.
If you place a market order, then there's no difference; each leg of the basket will be sold at their current bid prices.
If you want to ensure that you get a specific price for the basket as a whole, then you would put in a limit order for the basket. If you put limit orders on each leg, there's a chance that only one will be executed, which will leave you with a position that you did not intend.
The advantage to placing an IC order is that you get a fill at your price or no fill at all. If you leg in and you get a a fill on one side and price moves against you, your fill on the other side may be ka-ka. With that said, there are some subtle advantages to legging in.
There are 3 ways using combo orders to open an IC. The first is as an entire order. The second is as a pair of vertical spreads and the third is as a pair of strangles. If you set up all 3 orders, sometimes people may bid up (or down) the price of a vertical or a strangle and the total price that way is slightly better than the total offered for the IC. Most of the time this is meaningless you see more of it when there is pending news and increased option activity (such as just before an earnings announcement).
In my experience, combo orders like IC-s with many legs aren't filled as often as smaller combos like straddles, strangles, verticals, etc.
Let's take an extreme example for illustrative purposes. Suppose the wings of the IC have a price of 5x10 cents. I'm not going to get any price improvement there so I will try to work the selling of the body via a short strangle. The moment I get a fill, I buy the wings strangle at the market.
Do not attempt to leg into any position via the short legs first unless you have experience and you are a disciplined trader.