Broiling involves high heat coming from a source very close to the surface of the food. It is appropriate for thin food, or for adding color (via caramelization/Maillard reaction) to already (or mostly) cooked items. I couldn't say what the temperature of the heating element itself is, but the resulting air temperature is usually upwards of 550˚ F (288˚ C).
In baking, although the heating element is usually on one side or the other of the oven,* the idea is that heat is being transferred to the food more or less evenly from all sides. This is part of the reason thorough pre-heating is important -- to make the air in the box all the same temperature before the food goes in. There's no real "default temperature" -- you use whatever will produce the desired results in your food.
With lower heat, coming from all sides, baking will allow the interior of a thick piece of food to cook before the exterior has over-cooked. Putting cake batter under a broiler will likely result in a dried-out or burnt top, perhaps a layer of reasonably well-cooked cake, and a raw bottom. The heat simply won't transfer through the cake fast enough to allow the entire thing to cook.
The appropriate technique for meat depends on the size of the meat. Steaks can do very well under a broiler -- the intense heat allows the exterior to brown and become flavorful without the interior over-cooking. A roast cut or a whole bird, on the other hand, would need to be baked (or "roasted") so that the interior has time to come to the proper temperature. A very thick chop or steak might be started in the oven, then finished under the broiler to give it color.
*Your oven probably has just the one heating element, used for both baking and broiling. There's no reason that an oven couldn't have multiple elements for baking -- and it might produce more even cooking -- but broiling always means heat from above.
Turning down the temperature by 20C was a good idea because of the fan, however it may be too much in your oven's case as it sounds like the temperature was a bit too low.
What likely happened was that the fan blowing over the center of the bread cooked the center first, but the fan didn't blow on the sides of the bread as much. This has happened to me when I'm using a high sided baking tin where the bread was not up to the top. I find when baking breads and cakes that the fan tends to char the outside of things even if I turn it down, and then the inside doesn't cook so well, so I usually leave the fan off. I suggest you try the recommended temperature with the fan off and see how that works.
Best Answer
The reason for turning the food when baking is so the side that is in contact with the pan can get hit by the hot air. In the case of turning on the bake and then turning on the broil, you would still have the medium of what ever your food is sitting in.
If you are willing to elevated your food above a drip pan, turn on just the bottom heating coil (if possible), and set the food directly on the rack you could eliminate the need of turning halfway through the process.