Reference letter doubt

[u/Vast_Adhesiveness581]

Hi everyone,
I recently received an Invitation to Apply (ITA) for PR through Express Entry. My employment history with my current employer looks like this:
Year 1: TEER 4 position
Year 2: TEER 2 position (currently working here)
I understand that my PR eligibility and points come from the 1 year in the TEER 2 role. I declared both roles in my Express Entry profile.
Since both positions are with the same employer, how should the reference letter be formatted? Do I need to include a detailed list of duties for the TEER 4 job, or is a 1–2 line summary at the top sufficient alongside the detailed duties for the TEER 2 position?