BPMN21 — Replace "process" attribute of a laneSet with "flowElementsContainer"?

In BPMN2.0 beta1 LaneSet had a relationship with Process. This was changed in beta 2 and now LaneSet has a relationship with FlowElementsContainer, with the exception of Choreographies or Sub-Choreographies (see Figure 10.126 - The Lane class diagram ). In Table 10.134 ­ LaneSet attributes and model associations (of BETA2 document ) I see that there is a process attribute described as "the process owing the Lane set". Shouldn’t there be a "flowElementsContainer" attribute (as the LaneSet can be owned by a Sub-Process too) instead of the "process" attribute?