Q. What documentation should be maintained for a SEPP plan? 

A. The safe course of action is to document the plan and all plan transactions. 
Develop a written document that outlines all pertinent details of your SEPP plan. There is a sample form on the https://72tnet.com website that can be used a guide. 

Also keep original copies of the account statements that were used to determine the initial payment and any recalculations. Additionally, keep copies of the statements reflecting each withdraw as it occurs.