What is the basis for a kohen who is the shatz to do Birkat Kohanim even if there is more than one kohen present like is done in at least a few Israeli Ashkenazi communities? The Shulchan Aruch states in siman 128, sief 20:
אם ש''צ כהן, אם יש שם כהנים אחרים, (עב) כ''ג] לא ישא (עג) את כפיו
If the shatz is a kohen and there are other kohanim he does not do Birkat Kohanim.
Seemingly this means that if the kohen is the shatz and there are other kohanim present he should not do Birkat Kohanim, yet in some communities the kohen shatz does go up and perform Birkat Kohanim. I checked the commentaries and could not find any answers so maybe other people have heard an answer for why some communities allow a kohen who is shatz do Birkat Kohanim when there are other kohanim present.