I'm trying to grasp the tables used to reduce timing at increased IAT and ECT temperatures. There are two tables used for this which I'm including. These are the stock tables.
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As IAT and ECT raises, the ignition delay decreases and I'd want to reduce the timing most at these points. I'm trying to understand what is actually happening with these tables. Let's say at the highlighted points where the multiplier is 0.40 and the retard is 5. To me this would be 5*0.4=2. Is this the value that is subtracted from the main timing table? When the value is negative is it actually increasing timing?

Also wondering what a multiplier of 0 does? Since I want to retard the most when the multiplier table is at "0" on the outside rows and columns, I'd expect to see the opposite with a value of 1. Any input would be appreciated.

Thanks!