If you give the route to ITA (and select the class you're flying) it will give you a list of every tax, fee, and charge for every segment. I can't see why these would be different when the segments are flown as an RTW.

A stab at it comes up with these charges converted to USD. Business class or higher. Trip begins in June and everything was probably considered a stop-over, since I spaced days to avoid thinking about them. ITA made me do six segments max, hence the groups

KRT to BOM:
$861.69 Sudan Stamp Tax (SD)
$149.06 (YR)
$5.25 RJ YQ surcharge (YQ)
$6.81 Sudan Passenger Service Charge (NY)
$602.68 BA YQ surcharge (YQ)
$6.62 Jordan Civil Aviation Transfer Fee (KJ)
$265.82 United Kingdom Air Passengers Duty (GB)
$55.27 United Kingdom Passenger Service Charge (UB)
$31.91 Hong Kong Departure Tax (HK)
$157.24 CX YR surcharge (YR)
$25.10 Rep. of Korea Intl. PSC, Dep. Tax (BP)

$2,167.45 sum for these six (reduce APD if LHR is a transit)

BOM-HKG (forgot it in the groups of six)
$80.24 Indian Service Tax (JN
$124.42 CX YR surcharge (YR
$4.18 Indian Passenger Service Fee (WO
$12.11 Indian Development Fee (YM

$220.95 sum for BOM-HKG)

HKG to IAH
$10.06 USDA APHIS Fee (XA)
$14.18 US Immigration Fee (XY)
$11.09 US Customs Fee (YC)
$33.53 US International Arrival Tax (US)
$125.46 AA YR surcharge (YR)
$15.47 Hong Kong Departure Tax (HK)
$15.47 US September 11th Security Fee (AY)
$1.55 Barbados Airport Facilitation Fee (DI)
$16.76 US International Departure Tax (US)
$4.51 US Passenger Facility Charge (XF)
$27.72 Barbados Passenger Service Charge (JG)
$2.58 Barbados Security Fee (JH)

$278.39 sum for HKG to IAH

IAD* TO KRT
$300.00 AA YR surcharge (YR)
$4.00 Toronto Airport Improvement Fee (SQ)
$0.50 Canadian Harmonized Sales Tax (ON) (RC)
$16.70 US International Departure Tax (US)
$5.00 US September 11th Security Fee (AY)
$7.50 US Passenger Facility Charge (XF)
$26.90 Cyprus Airport Service Charge (CY)
$0.60 Cyprus Passenger Service Charge (JX)
$2.40 Cyprus International Passenger Terminal Facilities Charge (JW)
$210.50 United Kingdom Air Passengers Duty (GB)
$38.60 United Kingdom Passenger Service Charge (UB)
$0.60 Cyprus Passenger Service Charge (JX)
$56.50 Jordan Embarkation Tax (HQ)
$8.50 Jordan Passenger Terminal Use Fee (NH)
$678.30 sum for IAD to KRT

This last group meanders a bit and the IAH confused me, as ITA didn't find a direct route. Maybe day specific.

That all adds up to $3,345.10, half again higher than the Eu1550 you mentioned. The Sudan Stamp Tax and BA's YQ in the first group look suspicious, and of course transiting LHR will save perhaps $300.