Join Date: May 2006
Location: New York, London, Sydney
Programs: United GS/2MM, DL*P, VS*G, AA*EXP, Avis CHM, Hertz Platinum, Sixt*D, HH*D, HGP*P, Starwood*P
Posts: 9,879
You're not buying a Y seat and upgrading the infant. You buy yourself the Y seat, upgrade yourself, and then buy the infant a J "seat." (ie 10% of the J fare, not the Y fare)