We are looking at a J Oneworld RWT
HND-HKG-YVR-DFW-MIA-BGI-LHR-ARN-DOH-CAI-DOH-DPS-SIN-MEL-AKL-SYD-HND.

DPS-SIN on jetstar. A lot of these flights are transit to get to a destination, ie DOH is a stopover to both CAI and DPS

Is this allowable? If not, can someone please point out in simple terms where I have gone wrong.
Much appreciated.