Actually, it doesn't need to be on the same ticket for visa free connection in DEL. You just need to have confirmed onward ticket within 24 hours, but actually, you don't get checked at all in DEL so even if it's more than 24 hours, I'm not sure how they can catch you. Anyway, confirmed res <24hr on Jet/Kingfisher DEL-KTM = no need for transit visa in DEL.

When we went last year, my boyfriend was on award ticket, so one ticket all the way to KTM via DEL. I was on revenue ticket, so had to buy two seperate tickets since if DL issues my ticket all the way to KTM including the Jet leg, it would effectively costs me over USD 1,000 on that last DEL-KTM flight!

Not only that, we also had an overnight connection in DEL - less than 24 hours, but landed in DEL in the evening (late evening) and didn't fly out to KTM from DEL until early morning the next day. I researched the forum here and also lots of posts on lonelyplanet and concluded that I, as an America, even though on two separate tickets would still be able to connect in DEL without a visa. I even printed out the visa regulation page from DL's database and brought with me just being afraid that I'll be denied boarding with no Indian visa. But no question was asked when I took the actual trip

Long story short, with the new terminal in DEL, it is very easy to connect. There's absolutely no need for transit visa in DEL if you have a confirmed connecting flight within 24 hours. So don't worry if you can't get award inventory and end up needing a second ticket to KTM.