Hello to all, my first post to flyerTalk!

I've been flying from MCI to KUL for a few times before...

Northwest: MCI - MSP - NRT - SIA (6 hours layover from 12am to 6am) - KUL
Southwest and CX: MCI - LAX (layover until 1am Pacific) - HKG - KUL (Bought WN separately)

I'm planning on going to KUL again in May/June, which means I'm running into shoulder/high season. The local agent quoted the following route with CO and SQ as US$14xx:

MCI - IAH - DME (refuel) - SIA - KUL

but the problem is the leg from IAH to MCI in June, as CO ran out of the $150 tickets for the 5pm flight departing IAH, which the agent suggested the wait-and-see approach. I checked Expedia.com for MCI-IAH... another CO flight in the morning would cost $340 ai, but the 5pm would cost $600 ai!!

Can someone suggest an alternate route with similar price, or what I can do about the IAH to MCI non-stop? I'd hate to have another stop between IAH and MCI given the long flight from SIA to IAH...

Thanks in advance!