41C sunrise/sunset program listing: what are these strange "dot" steps?

[Thomas Okken]

Looking at the DOY routine, the dot in line 8 has to be a minus in order for the code to make sense. However, line 11 should be FS? 31, not FS? 01. And how would a minus get turned into a dot while there are normal minuses elsewhere in these listings? I don't think I'd trust this code...