To get the GI for a specific fare, you need to refer to the Routing Rules display (as long as the fare is correctly filed with a unique Fare Basis code):
[KVS Availability Tool 5.1.4/Diamond - Routing Rules: DEL-MOW/YY/CIF/5834 USD]
Code:
DELMOW-YY 15NOV09 *RULE DISPLAY* TARIFF 0004 RULE ESAS
* ADD APPLICABLE TAX * FED INSP FEES *
-FARE BASIS INR NUC PTC FT GI
CIF R 271975 5594.12 ADT NL EH
CIF R 271975 5594.12 CNN NL EH
CIF R 271975 5594.12 UNN NL EH
CIF/IN90 R 27200 559.40 INF NL EH
CIF R 271975 5594.12 INS NL EH
BOOKING CODES ENTER>S E SPECIFIC AIRLINE FARES DISPLAY.
INDUSTRY FARE TYPE - BU - BUSINESS CLASS UNRESTRICTED
MPM - EH 5452 VIA EASTERN HEMISPHERE
---------------------------------------------------------------
MPM CONSULT ROUTINGS TARIFF
My point was that for the lower YIF fare (via FE) the routing rules cannot be retrieved in KVS at all [the rules which show up are for the higher fare], hence you can only guess (or ask a TA) what GI is to be used.