I think it's when they force the 200mg/ml mix. That said, there are times I used 800mg+ of those kinds of mixes per week and never had problems either.It’s always surprising to me when I read of members getting pip from primo as it has been a staple for me for years and I don’t recall one instance where it has gave me pip.
Personally I’m loving Opti’s line and I am not really a gso fan but find Opti's gso to pin quickly and smooth. For transparency I do use a coffee mug warmer and heat my oils a bit.