It is just like any other trip; if you throw away a segment all the others remaining are canceled.
The *A RTW fares should be a few thousand cheaper ex-WAW than ex-NYC from what I'm seeing (i.e.
http://www.wandr.me/RTW_Fares.aspx/ByProduct/CRWSTAR2); I'd be surprised if you're really seeing the opposite.
And the booking classes for the RTW on the various carriers are thus:
RTW BOOKING CLASSES BY CARRIER
Code:
CXR FIRST BUSINESS ECONOMY
A3 C NOTE 1 D NOTE 9 M
AC C NOTE 1 Z NOTE 2 M
BD C NOTE 1 D NOTE 3 M
CA A NOTE 4 D NOTE 5 M
F WITHIN CN C WITHIN CN M
NOTE 6 NOTE 7
CO D NOTE 3 Z NOTE 2 M
JJ A NOTE 4 D NOTE 3 M
JK C NOTE 1 D NOTE 9 M
JP C NOTE 1 D NOTE 3 M
KF J NOTE 10 Z NOTE 11 M NOTE 18
LH A NOTE 8 D NOTE 3 M
LO D NOTE 3 Z NOTE 2 M
LX A NOTE 8 D NOTE 3 M
NH A NOTE 8 D NOTE 9 B
F WITHIN JP Y WITHIN JP Y WITHIN JP
NZ C NOTE 12 D NOTE 13 M NOTE 19
MS A NOTE 8 D NOTE 3 M
OS C NOTE 1 D NOTE 9 M
OU C D NOTE 3 M
OZ A NOTE 8 D NOTE 3 X M
Y WITHIN KR Y WITHIN KR Y WITHIN KR
SA A NOTE 8 D NOTE 3 M
SK J NOTE 10 Z NOTE 11 M NOTE 18
SN C D NOTE 3 M
SQ A NOTE 14 D NOTE 3 M
TG A NOTE 8 D NOTE 3 M
TK F NOTE 15 D NOTE 3 M
TP C NOTE 1 D NOTE 9 M
UA A NOTE 4 D NOTE 5 M
US A NOTE 16 Z NOTE 17 M
----
NOTE 1 IF C NOT AVAILABLE BOOK Y.
NOTE 2 IF Z NOT AVAILABLE BOOK B
NOTE 3 IF D NOT AVAILABLE BOOK Y.
EXCEPTION FOR TG ON DIRECT SERVICES
TO/FROM USA
IF D NOT AVAILABLE BOOK U
-OZ MANDATORY BUSINESS CLASS SURCHARGE
ON ROUTE ICN-SFO/LAX.
SEE PARAGRAPH SURCHARGES.
NOTE 4 IF A NOT AVAILABLE BOOK C.
IF A NOT OFFERED BOOK C AND
IF C NOT AVAILIBLE BOOK Y.
NOTE 5 IF D NOT AVAILABLE BOOK B.
IF D NOT OFFERED BOOK A AND
IF A NOT AVAILIBLE BOOK B
PROVIDED THAT ONLY FIRST AND ECONOMY
CABIN OFFERED ON THE FLIGHT.
NOTE 6 IF F NOT AVAILABLE BOOK C.
IF C NOT AVAILABLE BOOK Y.
NOTE 7 IF C NOT AVAILABLE BOOK F
IF F NOT AVAILABLE BOOK B
NOTE 8 IF A NOT AVAILABLE BOOK C
NOTE 9 IF D NOT AVAILABLE BOOK B
NOTE 10 IF J NOT AVAILABLE BOOK D
IF D NOT AVAILABLE BOOK Y
NOTE 11 IF Z NOT AVAILABLE BOOK Y
NOTE 12 IF C NOT AVAILABLE BOOK U
IF U NOT AVAILABLE BOOK Y
NOTE 13 IF D NOT AVAILABLE BOOK E
IF E NOT AVAILABLE BOOK B
NOTE 14 IF A NOT AVAILABLE BOOK J
NOTE 15 IF F NOT AVAILABLE BOOK C
NOTE 16 IF A NOT AVAILABLE BOOK D
IF D NOT AVAILABLE BOOK Y
NOTE 17 IF Z NOT AVAILABLE BOOK B
IF Z NOT OFFERED BOOK A AND
IF A NOT AVAILABLE BOOK B
PROVIDED THAT ONLY FIRST AND ECONOMY
CABIN OFFERED ON THE FLIGHT
NOTE 18 FOR ECONOMY EXTRA BOOK S
SEE S CLASS SURCHARGE IN PARAGRAPH
SURCHARGES.
NOTE 19 FOR UPGRADE TO PACIFIC PREMIUM ECONOMY
BOOK O. SEE NZ O CLASS SURCHARGE
IN PARAGRAPH SURCHARGES.
NOTE 20 IF A NOT AVAILABLE BOOK D.
NOTE 21 IF J NOT AVAILABLE BOOK Y.
----