StarAlliance RTW fare such as STAR1, STAR2, STAR3 has one stopover per one city restriction, and maximum 3 transfer at same city restriction.
However, AONE/DONE/LONE Oneworld Explorer fare does not have such restrction. Sometimes, people are confused.

I use following route a few times.

CAI-xLHR-HKG-NRT-HKG-NRT-HKG-(-NRT-HKG-)-YVR-...-CAI
(-NRT-HKG-) is extra paid additional segments.

In this case, I stopover at HKG 4 times, fly HKG->NRT 3 times.
No problem.