Poncho Unisize Luxury Design No. 62 -- the collar

Hello everyone,
I have already sent a message to the designer, but I’m not getting a reply (maybe because of vacation?). I’m not quite sure about the collar of the poncho. Shouldn’t there be decreases so it fits more closely around the neck?
Poncho

Or does it narrow by itself if I insert the hook only into the back loop of the stitch?
Thank you very much for your help
Best regards
Anja

Hi, unfortunately I’m not familiar with the pattern myself. But I noticed in the description that two different yarns and two different hook sizes are listed. Is the collar crocheted with the thinner yarn and the smaller hook? If so, I can imagine that it’s supposed to be done without decreasing, which would make the collar smaller. 

Thank you