[BPCS-L] Question on allocations and default warehouse

["Jim" <jmergen@xxxxxxxxxxx>]

Hi

Does anyone have the BPCS rules/hierarchy on how parts are allocated to a
Shop Order. From what I understand:

IF in IIM(Item Master) we use a default location, then at Shop Order
Print(SFC520 as SFC500 doesn't actually allocate until print runs) parts
from the default location will be allocated, if inventory exists, but from
this location ONLY.

IF in IIM there is no default location, then it will try to allocate
available inventory beginning with the first location with
inventory(alphabetically).

We have a situation where several parts did not allocate, although there was
inventory on-hand.

Some of the parts didn't allocate, I believe, because of a default in IIM
not matching locations where inventory exists(I reason for not using a
default in my mind).

Some of the parts didn't allocate, didn't have a default location in IIM,
but did have available inventory in at least one location.
As a test on one of these parts, I updated IIM default location to a
location that had inventory, ran SFC400(batch allocations) and the parts DID
allocate.

This confuses me-I cannot figure out why, with the default location in IIM
set to BLANKS, and available inventory existing in at least one location(Yes
warehouse and location are defined as allocatable) it didn't allocate the
parts, but then when I entered a default and ran SFC400 it did allocate.

Does anyone have a set of comprehensive rules that define how BPCS
allocates, other than the  vague help screens?

Also, can anyone point out reasons for and against a default location in
IIM?

Thanks for any guidance

Jim