Totally agree with you.
Can you explain what you mean by thus
They mean that the English translation in R15 (the version without smut scenes) has better quality of the English translation and its also the official translation but all the smut scenes are cut or censored. The other version that includes the smut scenes(R18) is available with a fan translation but its English translation quality is comparatively poorer/is off.
Both versions are available here.
So its difficult to understand the story if you're reading the R18 version with fan translation.
do some justice for the translation in the mature version.. i can understand r15 better, but it's a bummer to read the story with censorship.