I was trying to price a mileage run on ual.com, leaving for Europe on Saturday and returning on Sunday (so a few hours stay in Europe). The individual (non stop) legs price at $175 and $172, but when I choose these legs it prices it to $526.40. Is the additional amount (roughly $180) taxes and fees?

Now I choose some alternate routings which go through Chicago/Washington hubs instead of the non-stops. The one ways are priced at $177.50 based on a RT purchase, but when it goes to the next screen for the RT it prices at $1541.40. What is going on here?