Hi, Bijana,
If I may answer your question directly and in one word, I would say "immediately"
Indeed, if you wish to grow with SFI business and maintain and sustain your leadership positions across the board, it is by growing your PSAs. This is because, the more PSAs you have, and the more active those PSAs are, the more action VPs you will acquire.
So, you should start buying PSAs to go immediately from now onward.