Why are sequencing reads shorter than PCR products?
Reliable sequencing reads start usually 50bp downstream from start of primers. Which means that 180bp-band (on the gel) sequenced with one primer will yield readable sequence in region 50-180bp (130bp length). Also I notice that sequences usually reported somewhat before reliable data, i.e. clean data starts after 52-55bp, but sequencing reports basepairs downstream from 48bp after primer start.

If you need whole-band sequence, you will have to sequence with set of two primers, each in different direction. Since you PCR this band, you already have your sequencing primers.