On our 5008 machines the bicarb conductivity straight from the bibag is around 60mS. The conductivity straight from the acid cell is around 190mS (I think from memory). Mixing it with the appropriate amount of water gives us our conductivity governed by the prescription settings on the machine. Are you on a 4008 by any chance where you have to take the amount of acetate in the acid can into consideration when setting your bicarb using the "+/-" feature?
I don´t know Fresenius machines but I know others like COBE, TORAY, NIKKISO and NIPRO. 24 year experience and still learning every single day.
Below you can see the chart I was looking for.
The bicarb to conductivity correlation matches exactly with the one I have calculated using a Roche 9180 measuring total sodium and total chlorine.
Good to know others have a similar experience.