Similar question, I was looking to book MSP-MRS. If I search it as a one way the price is 57.5 and $757. If I split it to MSP-LHR and then LHR-MRS via the multi city search I get a price of 82.5k and $28. It does not let me book the latter online but says to call. I haven't called yet to try it but maybe it goes against their routing rules. Anyone know? Thanks