There are three different planning process types:
Regenerative planning: processing key NEUPL
Net change planning in the total horizon: processing key NETCH
Net change planning in the planning horizon: processing key NETPL.
In order to speed up requirements planning, it can be limited to a certain
planning horizon with the processing key NETPL. Only those requirements
that are within the planning horizon are then covered by receipts.
As time passes, requirements can fall in the planning horizon even thought
they have not yet been covered by receipts. If no other changes relevant to
planning occur, these requirements will only be covered during the next
planning run over the entire time frame (with processing key NETCH or
NEUPL). So that these requirements are also taken into consideration,
execute a net change planning according to the net change procedure
every so often, using processing key NETCH.
Planning with the processing key NEUPL concerns regenerative
planning. The system plans all materials that are included in the planning
file, irrespective of the indicators.
If you change settings in Customizing for requirements planning, such
as settings for a MRP type, a lot-sizing procedure or the purchasing
processing time, the materials affected by these changes do not have a
change indicator in the planning file. A planning run with processing key
NETCH or NETPL does not consider these materials, if planning file entry
NETCH or NETPL is set for a material. After these changes, it is therefore a
good idea to start a planning run with the processing key NEUPL, so that
the Customizing changes become effective. All materials in the planning
file are therefore considered in the planning run.
Hope it helps.