I was under the impression that base production is the same and upgrades changing from multiplicative to addictive is what results in declared production loss. Atleast if you hover over farmer it still says that he gives you 2 base plant fiber just like it used to before patch (I think). And the timer to fill to full capacity seem to be in line with those numbers. I did also lose a ton of gold gain but I assume it has to do with merchant treasures getting nerfed (I have 2 of those). But might be I'm completely wrong, I haven't checked it in great detail.