ROE is rate of exchange (not really applicable here. In a revenue ticket it would be the rate of exchange from NUC to the currency the ticket is issued in, rounded according to certain rules)

In the PDF there will be 2 taxes not included in this line and listed elsewhere, then everything is after XT (extra taxes). You are correct it is amount followed by tax code.

YQ and YR are carrier surcharges

SQ = CA Airport Improvement Fee
SW = JP Passenger Service Charge
TS = TH Passenger Service Charge
D5 = ID Passenger Service Charge
E7 = TH Advance Passenger Processing User Charge
G8 = TH International Arrival and Departure Fees