There's a lot of misinformation and mischaracterization in the OP's post. Here are the actual fees on a DL SEA-LHR-SEA non-stops business class award found by the hyperlink TOTAL PER PASSENGER on the Review Itinerary screen:

DETAILED CHARGES

Air Transportation Charges

Base Fare*0.00


Taxes, Fees and Charges

U.S. Animal and Plant Health Inspection Service Fee 5.00

U.S. Custom User Fee 5.50

United Kingdom Passenger Service Charge 75.80

United Kingdom Air Passenger Duty 235.70

U.S. September 11th Security Fee 5.60

U.S. Immigration and Naturalization Fee 7.00

Total Per Passenger 334.60

Air Passenger Duty has a 'standard' rate for premium cabins and a 'reduced' rate for coach. Here are taxes and fees on the same routing for a coach award:

DETAILED CHARGES

Air Transportation Charges

Base Fare*0.00


Taxes, Fees and Charges

U.S. Animal and Plant Health Inspection Service Fee 5.00

U.S. Custom User Fee 5.50

United Kingdom Passenger Service Charge 75.80

United Kingdom Air Passenger Duty 117.80

U.S. September 11th Security Fee 5.60

U.S. Immigration and Naturalization Fee 7.00

Total Per Passenger 216.70

Everything but UK APD is unchanged. APD is a departure tax: it is avoided when transiting the UK (<24 hours) or by departing from an airport not in the UK.

Here is a Business class SEA-LHR, AMS-SEA award tax/fee breakdown:

DETAILED CHARGES

Air Transportation Charges

Base Fare*0.00


Taxes, Fees and Charges

U.S. Animal and Plant Health Inspection Service Fee 5.00

U.S. Custom User Fee 5.50

RN Tax 20.90

VV Tax 2.70

B Tax 0.00

CJ Tax 17.30

U.S. September 11th Security Fee 5.60

U.S. Immigration and Naturalization Fee 7.00

Total Per Passenger 64.00