Wheat max 400, but l I see higher values ?

OK, this puzzles me.

how it this possible?

http://www.safeunderdark.com/_Content/wheat.jpg

I noticed this yesterday as I got a wheat refill from the Dark Priests adventure containing 600 wheat. The field said 404 when I hovered over it with the refill and 1004 after the adding. Also today, this morning, when I again hovered over it once again it says 404 wheat. The closest buildings to this field is 2 lvl 3 silos and the farms (also lvl 3) closest to this field has other fields as their first priorities before going to that field so no way it could have been extracted 600 wheats over this night. Could it be some kind of bug maybe?

Like a Fish Deposit, or a Meat Deposit, you can keep adding refills to Wheat fields.

Before the Silo's were introduced to the game, I had several farms around one field, which I kept topped up to a minimum of 100,000 wheat!

A silo will actually refill a field to just above it's max (for example, if a field drops to 399 wheat, and the two nearest buffed Lv 5 silos decide to refill it, it could jump to 419 before the farm takes any more out. The silo should then ignore this field until it drop below 400 again.

Yep I'm aware of the refill function of deposits and your explanation of the silo refill function seems all logical :) But just don't exactly know how 600 wheat can "disappear" over a night since the closest farms have other fields as first priority and for 3 nearest lvl3 farms on 9 hours (the time I was away) would have extracted 378 wheats from that field if they had that one as their target which they didn't. It's not bugging me it have gone but I maybe just could have missed something but seems a bit odd anyways.