Your project hours are projects the you DIRECTLY led only. Do not count project hours that you were only a team member on OR that you didn't actively lead. It will help when you are potentially audited as your employer or whomever is vouching for you will be able to honestly confirm your statements.
I'm not entirely clear on what you're driving at with regard to your question.
Hours don't overlap with respect to being involved in multiple projects "simultaneously." An hour I spend on project A (e.g., communicating with a stakeholder) doesn't also count towards project B.
For example, if you are managing two projects in the month of July and spent 40 hours on Project A and 60 hours on Project B, you have 100 hours of PM experience for July. As far as MONTHS of experience, this contributes only 1 month, regardless of you being involved in multiple projects.
With regard to roles other than PM that you fulfilled on project teams, they are not relevant in terms of the PMP certification.
Does this mean that you can use overlapped project management hours if you led the project. But if you were a project team member the project hours can't overlap ?
Number of Hours that You Led or Directed Project
Consider all of the projects that you have worked on and identify how many hours you spent leading and
directing the project. For this section of the application, if you worked on multiple projects at one time, all
the hours count toward the total.