Back to the basics.....Once you know what the conversion rate is, all you need to know is the inputs as long as the input materials are constant.
Sure it would be nice to have individual processors output but it is by no means essential.
The bottom line is how many gallons of fuel are made and sold by the company.
If I recall correctly the company is required to keep accurate logs of the amount of materials going into the processors. That information combined with the common tank levels provides a pretty good check on the ongoing conversion rates.
As for the issue of not accumulating the fuel into separate tanks, that is another non-issue. Each system output can be and is monitored by samples taken to the onsite lab on a regular basis. Loads are sampled and monitored by the lab for QC. Not to mention the computer and operators monitoring the machines.
That system will catch any QC problems faster than running the outputs to separate tanks would. Assume that they are doing what you suggest and running the output to separate tanks. Any problem with the fuel will be caught faster by the regular output sampling faster than by sampling the tank. If there is an issue with fuel going into the tank, it is diluted by the tanks contents. So what ever the issue is has to move the contents of the total amount of fluid in the tank out of spec limits before it is noticed.
Yeah, having the output in a separate tank allows it to be segregated. However a load out time the contents of the separate tanks will be mixed together.
So to do it the way you suggests increases the tank count by a factor of 3 or more for very little benefit with the attendant costs in pumps, piping, valves, real estate, on going maintenance and tanks.
