These may be contractual obligations we have no way of knowing about. Don't assume.
Also, I think the side stories are published in a different (but related) magazine - so they may have different terms sensei needs to meet.
They're not really published in a specific magazine actually. There's the two extras published in Pink Gold. And some other extras are exclusive to the limited editions of the volumes (not pre-published in any magazine). And there's obviously PixIV.
The rest are published in B-Boy Gold, the magazine Finder is published.
You want to see all book, magazine, and audio & dvd covers?
http://www.mangago.zone/home/album/14238/
Picture #2 is the magazine that Viewfinder debuted in (also provided is a link to the actual scan of that issue).
Table of contents of album:
2 Finder debut
3-28 Japanese editions
29-59 Magazines
60-63 Art books
64-72 CDs & DVDs
73-85 English editions
86-93 Korean editions
94-103 Chinese editions
104-113 Thai editions
114-124 German editions
125-133 French editions
134-138 Italian editions
139-141 Polish editions
Ah, thanks!
Wow, thanks J
Why does Ayano have time to write side stories but we have to wait for chapters with the main storyline