as i mentioned before i payed lab rats in many versions before this one , and never had trouble making money.
i dont do it alone i have employees in every department and all in the highest class which is currently available for now (5))
But i think it is ridiculous the cost of a serum is for example 80€ and the profit is only 4€ but also decreasing by the day
i also think a game is allowed to be difficult , there must be a goal to achieve and to easy is boring as hell but now it is to hard
or i made some mistakes which i dont oversee at the moment
The production cost it is talking about is not money!
It is based on the work your worker can do. You know that variable the girl and you have in the production skill set.
So if your skill is 40 it will take 2 turns to complete a batch of serum. If it is 30 it will take 3 turns and the extra production you put into it will go into the next batch.
When making a serum and researching it. Stop the turn before you finish researching it. Save. Then finish it. Tell Stephanie to "Finalize" it. Then review serum see if there is any flaws. If there are reload it the save just before you finished making it and try again. It can take a few times depending on how well you researched stuff. The worst ones that have 100% or more research down to at least 50% before even trying to make anything with them.
Some serum negative traits cause permanent damage to female characters. You could end up turning them into useless characters. So having Stephanie test it is no longer a good option of unless you know before hand it is safe.
Also if you use my mod. You will find it a lot easier because I fixed stuff like the contract system to actually be usable and work with you. The girls stats, skills and likes are tied together. So finding a girl that is useful is a lot easier.