Part number suffix meaning (,135 ,115)
Those numbers are related to ordering and packaging, see https://www.nexperia.com/products/bipolar-transistors/general-purpose-bipolar-transistors/transistors-single-npn/BC847BW.html and scroll to the ordering section.

The 115 is a 7" reel of 3k pieces, 135 is an 11 1/4" reel with 10k pieces.