Are you saying that an aircraft , that's been in production for 20 years will cost more than a brand new still in development??
http://asw.newpacificinstitute.org/?p=11207
F15K cost $100mil inc spares and support - the SE will costs similar.
The FBW system has been paid for by Saudi Arabia for the F15SA ; the CBW are being designed by
KAI so its of interest for RoSK to support its own industries by going with the `SE` variant.
And the Japan discussions placed the F35 @ $238mil per unit.
Support its own industry and get more ` bang for your buck` -RoSK and Singapore both IMO will go for the F15SE.
Israel will likely get the `bolt on ` CBW as well.