How does this match barcodes

[dlzurich]

Hi, I am wondering what method this software uses to match the read barcodes to that provided? I am running it with different levels of mismatching (0,1, 2), but when I go from 1 to 2 the allocation of reads to certain barcodes is decreasing. My barcodes have been designed to be identifiable with up to 3 mismatches, so I was curious what could cause this and was wondering how the software selects the "correct" barcode if you allow mismatches?