I understand exactly what you're saying. The problem is with the calories showing, not the carb count. It would seem the calories are wrong, they seem a bit high to me anyway.
How big is the original package? Or,, how big is a serving, in grams or oz.? I think 10 oz. is the standard size for a pkg., so that would be 284 gm or 300 gm??
Anyway, from the USDA -
a 10 oz. pkg chopped frozen spinach
calories - 68.16
protein - 8.293
fat - 0.88
total carbs - 11.36
fiber - 8.52
so, 1/3 of a pkg. would be -
calories - 22.72
protein - 2.764
fat - 0.293
total carbs - 3.787
fiber - 2.84
Obviously, on your package, they've rounded up the figures, which is fine. But the calories are way out. That happens sometimes. My fave brand of x-firm tofu used to list the carbs as 12 gm per serving of 1/3 pkg...
... Then they got new packaging, what do you know, there's 12 grams in the whole thing, only 4 grams per serving -- minus fiber of course, which I had to look up elsewhere.
I also realise even so, that the total carbs still don't jive 100% with the listed sugar/starch/fiber numbers. Partly this is due to the rounding up of figures, and partly because, some of the fiber is soluble, meaning it is digested, and there is a caloric content, although it doesn't affect insulin or blood sugar levels. That's a whole long other ARTICLE I might write in the future, too much to deal with here. Long-story-short, don't worry about it.
Use the carb count minus fiber as listed on the pkg. Their calorie calculation is wrong, it's too high.
Doreen