I generally DO count all of the oil when I cook, but if there is visible oil left over in the pan, then you probably do need to consider this. I don't go all out and measure how much is left, but I do judge my meal satiety, and if the meal did not keep me covered for 4-6 hours, then perhaps adding a little extra oil would not hurt. No need to be exact!
When you are starting out, make all of your meals even with equal blocks of protein, carb and fat. I would not recommend shorting your carbs and adding more fat to cover for the missing carbs, unless you are someone who is carb sensitive and need to do this adjustment based on your carb sensitivity. Cutting it back as far as you describe in your post is too much, though.
And, actually, if your block allotment for the day is 20, I would divide it up into 4-5 blocks of each macronutrient per meal, and then divide the rest up into snacks variously spaced throughout the day.
Hope this helps! (I wasn't sure that I totally understood the second part of your question... hope I understood it correctly!)