Food quantity - crazy numbers?

That's correct. I'm assuming that's metric and that you didn't change it from the options. Anyway I usually get around the same amounts, except where your commas are I think there should be '.'.

Commas or not (you non-american, you!  LOL), if it doesn't add up, it doesn't add up, regardless. 
Unless metric changed to base 12 or something - they still should total up correctly.

I'll keep an eye and have real numbers if it keeps showing up.  Though I still don't have any way to screen capture that i know of.

I find it strange that they don't use the next higher weight prefix, 25kg is way better readable than 25000g.

The right side overlay have a problem with the field rations. Even when you ate all of it it can sometimes show that you have it.

On the top left it shows the correct amount of food.

Here's some of the wild numbers I've had today:

Edible    2k
Field Ration  13k
Muck Root  1k
Meal Lice  0
Mush Bar  2k
[even ignoring the field rations, 1+2 does not equal 2]

Edible  29k
Field Ration 13k
Muck Root 0
Meal Lice 4k
Mush Bar 24k
Lice Loaf 28k
[Again not sure how 4+24+28 add up to 29?]

Edible 64k
Field Ration  13k
Muck Root  5k
Meal Lice  12k
Mush Bar  46k
Lice Loaf 28k
[28+46 alone is greater than 64 = WTF?]

It doesn't even work if you try and see if Meal Lice might be a part of lice bars.  I like math, and math is not working here.