I'll be honest I don't think the mangaka has a same face syndrome because it feels they are absolutely able to make different looking character?? More like they just have a fetish or a thing for very specific looking semes and ukes. Like I know some people who draw smuts will make one character to look like themselves and the other to look like their type. So it might just be that. I won't complain tho cause I get to read these HOT WALL SLAMMING SEX between these gorgeous gentlemen for free