when you weigh it depends on what info you are using. in other words, most of the foods in the tracker are foods in their ready to eat state [so cooked for most things]. so for those foods you would want to weigh them ready to eat [cooked]. if you are using the info from the package, then you should weigh those foods how they came in the package, because nutrition info on the label is required to be for the food in the as is state it is sold in.
for zucchini, i would weigh the zucchini raw and use that number. then i would add in however much olive oil you cook it in.
for the steak, since it was already cooked, using the cooked weight and the tracker entry is fine [so long as the entry you choose does not specify that it is for raw]. if you had info from the steak package, and the steak was raw in that package, then you would have wanted to weigh it raw so that it matches the info you have.
-google first. ask questions later.