Thank you very much for that. I am in the process of trying to track this down now, though it is a rather challenging issue, as it appears to occur in very complex industry code which I did not write myself (although which may have been affected by some of what I have written over time).
Would you be able to run some tests to assist me in tracking down this issue (my time is rather limited, so the more that you can help with testing, the quicker that I can fix this)? I am trying to discover whether the problem lies in the actual goods storage at the industries or whether only the statistics are affected. This is more easily done with a producing factory than a pure consumer. If the problem is just with the statistics, then the actual production of the factory should be unaffected (e.g., for a factory with 50% coal and iron ore inputs, delivering 50 units of coal and 50 units of iron ore should result in the production of 100 steel), and this should be apparent from the actual number of goods present at the receiving station. If, however, the problem lies with the actual number of goods tracked as being used by the industry, the actual production will be affected, so considerably fewer units of (for example) steel will be produced.
I notice, for example, at the ironworks at 1102,643, that the storage is shown on the graph as 1 for coal, whereas in fact the storage is given in figures above as 174. This suggests that it may well be a statistical problem, but it would be very helpful to have confirmation before looking in detail at the rather complex code dealing with the statistics rather than the equally complex but very different code dealing with the handling of actual units of product.