I understand that we are short of the coder. (´・ω・`)
Anyway, I tested on the behavior of fields count.
Behavior on the number of fields currently does not work correctly in extended.An example of orchard:Issue #1:The orchard
always has the maximum number of fields unless disturbed by the terrain. That is, the function whose number of fields gradually increases as mentioned in the previous post has no meaning.
However, since growth related parameters are set in dat file, I think that this behavior is different from the intention of pakset.
(Note: I know that sheep farm does not fall under this.)
Vegetable farm does not reach the maximum number, but it notices that this is a well-formed rectangle.
There is a limitation that it can not spread more than 9 tiles from the center, so it never reaches the limit.
Issue #2: The lower limit number that can be deleted is not min_field
https://github.com/jamespetts/simutrans-pak128.britain/blob/master/industry/orchard.datOrchard1840 has an upper limit of 194 and a lower limit of 49.
In the case of automatic construction, it has 194 fields, and 194 fields are created as long as the terrain does not interfere with any value set manually.
This field can be deleted until it is 12, which is different from the minimum value 49.
After removing it to the minimum:

Orchard1750 has an upper limit of 104 and a lower limit of 26.
It also tries to have 104 fields from the beginning.
This field can be deleted until it is 6, which is different from the minimum value 26.
After removing it to the minimum:
https://github.com/jamespetts/simutrans-pak128.britain/blob/master/industry/arable-farm.dat1840's vegetable farm(ArableFarm1840) has an upper limit of 1942 and a lower limit of 365.
It also tries to have 378 fields from the beginning. This is the result of simply filling 9 squares around from the center. (19 * 20 - 2)
This field can be deleted until it is 91, which is different from the minimum value 365.
After removing it to the minimum:
https://github.com/jamespetts/simutrans-pak128.britain/blob/master/industry/cattle-farm.datCattleFarm1840 has an upper limit of 32 and a lower limit of 8.
This field can be deleted until it is
2. (It is a blank tile without a road.)
After removing it to the minimum:

Cattle farm did not know where to have the field, so I had to fill the removed places with the road.
This makes me annoyed when connecting the roads to the cattle farm. (´・ω・`)
12 is about 1/4 of 49, 6 is also about 1/4 of 26, 91 is also about 1/4 of 365.
https://github.com/jamespetts/simutrans-pak128.britain/blob/master/industry/sheep-farm.datSince Sheep farm has min_fields = 1, it is truncated to 0 when it is 1/4.
This matches the result of Elemental.
Where did this 1/4 come from?
Anyway, please note that the
minimum value is judged with 1/4 value but the maximum value is not divided by it.
Issue #3: The function of determine initial productivity range by randomly is broken
This implied in another thread by me, the function to determine the productivity range randomly is broken in Extended.
In other words, buildings are constructed with the same productivity. And even if "Production:" is set for manual placement, it is ignored.
This may be only for industries that fall under certain conditions.
For example, Fishery and sheep farm can be put with a initial random productivity. However, despite the fact that farms, orchards, butchers, bookstores and pubs are set to dat, they can not have ranged initial productivity.
As I guess from the example above, I think that the numerical value of some parameter used in the calculation is wrong.
EDIT:https://github.com/jamespetts/simutrans-extended/commit/42578b76528773cbf12499e6bb1c3981c220a5d0It seems specifications from Aug 2017 that the number of fields can be reduced to 1/4 of the min_fields value.