I think it is based on the time in the recipes file actually, I made a modlet that decreased the time of making certain high level recipes in the past and that was the value I changed:I think it has more to do with how times are rounded. The time it takes to process is based on the "weight" of the material. If you count 1000 individual items that are 1.3 grams and round each items weight value you get 1000. If you take them as a solid stack, it's 1300.