Type 1 Insulin and carb counting

This is such an "it depends" thing. I think the most common ratio of insulin to carbs tends to be 1:10 so they've assumed that for you, and probably suggested less just to be careful, to avoid a hypo. So yes 7 units for 80 grams of carbs is about right. But you'll just have to try it and see. The way it works is that after eating, your blood sugar should peak, often just outside the normal range, but hopefully not excessively, then come down again. But again, not so much you have a hypo. So if the peaks after eating aren't too high, and the low point afterwards isn't too low, you can assume you've taking the right amount......................subject to how accurate your basal is, but lets not even go there just yet.

It varies a lot. The only way to find out is by trying.
They often start you out on a 1 unit to 10 grams of carbs regime and work from there.