Good point. That isn’t very well explained. However, as the portfolio coverage (PC) method is binary and we’re using the temperature rating aggregation methods we can replace the outcome from the temperature rating method for the companies, i.e. TS, in the formula with the outcome of the PC-assessment, i.e. 1 if the company has an approved target or 0 if the company does not have an SBTi-approved target. This means that you can use the same weighting methods for both temperature rating and portfolio coverage. Simply replace TS with PC in the formula.
You can currently use whichever method you find most suitable that is listed in the guidance on p 152 onwards. However, SBTi prefers them in revers order of the listing in the guidance, as we see ROTS and AOTS as more robust.