Oh yeah, that's odd alright. Because it looks like only 53 st are involved in the writing of Line 13: specifically....you're doing the P13 4 times (which totals 52 st), then a single K1. That's a total of 53 stitches mentioned in line 13 directions) No wonder you have 5 stitches left instead of 1 for the K1.
I follow your problem.
Are you sure that your 57 stitch count at the end of Line 12 is correct?
Lastly, can you supply a link to the pattern so we can read it along with you? I'm not familiar with the pattern.
Mods and Members, do you have additional comments and help for us?