How is it possible that this "sub-calculation" of the "main calculation" actually gives a HIGHER value?
Imagine you keep track of all your purchases, from chocolate bars to houses and cars, over your entire lifetime. Maybe you buy 5,000 chocolate bars at prices varying between $1 each and $2 each.  For an average price of, for the sake of this example, $1.47.  Then you buy a car, priced at $40,000.  Now, the average price of the chocolate bars hasn't changed, but if you add in the car to that set, and recalculate the average you'll be at an average of something like $2.26.  That skew of outsized members of a set is why statisticians occasionally employ standard deviation to get rid of outliers.  In this example, if you remove any purchase from the set that has a price higher than 3 standard deviations from the mean, you return the average of the set back down to $1.47.
Your question shows that have two different sets of numbers that you're combining into a single larger set, eating in a restaurant, and getting delivery.  Imagine this is the set of purchases made in a restaurant:
╔═════╗
║ 134 ║
║ 129 ║
║ 105 ║
║ 118 ║
║  99 ║
║ 189 ║
║ 134 ║
║ 190 ║
║ 144 ║
║ 157 ║
║ 102 ║
║ 186 ║
╚═════╝
The average for that set of purchases is $140.58
Now, lets take the set of purchases for delivery meals:
╔═════╗
║ 289 ║
║ 275 ║
║ 209 ║
║ 189 ║
║ 305 ║
║ 190 ║
║ 232 ║
║ 287 ║
║ 200 ║
║ 270 ║
║ 186 ║
╚═════╝
The average for that set is $239.27.
If, however, you combine the sets together, as in:
╔═════╗
║ 289 ║
║ 134 ║
║ 129 ║
║ 105 ║
║ 118 ║
║  99 ║
║ 275 ║
║ 209 ║
║ 189 ║
║ 305 ║
║ 134 ║
║ 190 ║
║ 232 ║
║ 144 ║
║ 157 ║
║ 287 ║
║ 102 ║
║ 200 ║
║ 270 ║
║ 186 ║
║ 289 ║
║ 134 ║
║ 129 ║
║ 105 ║
║ 118 ║
║  99 ║
║ 275 ║
║ 209 ║
║ 189 ║
║ 305 ║
║ 134 ║
║ 190 ║
║ 232 ║
║ 144 ║
║ 157 ║
║ 287 ║
║ 102 ║
║ 200 ║
║ 270 ║
║ 186 ║
╚═════╝
The average is $187.70, which as you can see is less than the average for eating out, and higher than the average for eating in a restaurant.