objection: hearsay, your honor! it this official word? because they look like 2 grooves to me.'20-M was 'continuous' adjustability.
new Ti tips also have only 2 screen retention grooves since 2020. i actually like this change, always felt the middle one made too little difference but was very difficult to clean due to resilient trapped debris. a smoother bowl is also faster to reload IME (hugs 19M).