Hi, I'm not sure what you mean: there is Gcode for every N [*] layers to be inserted, and the Matl G-code <MATL> belonging to each material of the Material tab.
N[*] layer Gcode
As for the N[*] layer Gcode: for me it would be a better idea as well to change it to only insert Gcode at a given layer, and not repeated every N layers. But maybe others have more use of the repetitive Gcode insert.
Regarding your setting: what would be the problem when inserted a temp Command as M104 S220 T0 on, say, layer 45, and it will be repeated at 90 /135? It is resulting on a temp change on layer 45, and only 'confirmed' at the above layers?
Another solution would be to add it manually in a text editor / ReplicatorG or so, to manually add that command at the wanted position.
When using commands like: M104 S<TEMP> T<EXT+0> in the N[*] layer Gcode, you have to be careful (with dual extrusion) , as it reads out at the inserted position the temperature settings of the active extruder and belonging material.
Another option for this [N] layer Gcode is to add a longer cool periode each N layers, while lifting the toolhead a little, so it wouldn't melt the print, like:
G1 Z<Z+5>
G4 P60000 (wait for 1 minute)
G1 Z<Z>
Matl G-code tab <MATL>
Regarding the Gcode belonging to a material: each material has it's own specific Material Gcode. I used it for example to define extra retractions at extruder change for the support extruder, like this:
As such this Gcode does nothing: it has to be inserted at one of the PtrGcode tabs as <MATL> command
When using it for example on the "deselect extruder" tab, like this:
(**** DeSelect Gcode extruder change***)
It's resulting first in lowering of the temp of the inactive extruder, and then in the extra retraction as defined by the <MATL> command.
Wit dual extrusion: when inserted the <MATL> and other commands on the 'deselect extruder" Gcode tab: it reads out the temp material settings of the deselect extruder from the "keep warm" setting.
And when inserted on the 'select extruder' Gcode tab: it reads out all the settings of the active toolhead to start printing with (The Main temp of that material).
I used the <MATL> command a lot, for dual extrusion, when adding a long sequence of commands to do a extruder wipe next to the build platform, and pressuring the active extruder, and wipe it again at a toolchange. It took some time each extruder change, but resulted in an almost Ooze free dual extruder print.
In that way the variable as <X>, <Y> and <Z> are nice to use as well, to be able to do a wipe sequence and returning to the 'active' point of print.
Hope this helps a little.
Bart