A domestic exempt private foundation that qualifies as an exempt operating foundation under section 4940(d)(2) doesn't have to pay an excise tax based on the investment income. All other organizations are required to pay an excise tax.
The first year your organization qualifies for exempt operating status, you have to attach a determination letter which confirms your status along with the Form 990-PF. You just have to enter the date of the ruling or determination letter for all the other years your organization qualifies for this status. You are not required to fill Part VI of Form 990-PF unless your organization qualifies for the exempt operating status under section 4940(d)(2).