TL;DR
It's to add a type of quality condition that jumps automatically a certain amount of tiers depending on the integer.What?
The concept of the suggestion is to implement a signal that automatically detects a next tier depending on how much you need to add to another tier, as well as a way to upgrade the tiers automatically like how you can do with the default upgrade blueprint (It could be Ctrl+Left-click and Ctrl+Right click).The amount of + Tier should have the limit of the integer of the signals, as there's a mod that add unlimited tiers. (https://mods.factorio.com/mod/infinite- ... rom=search)
Example:
+1 Tier:
Left-click: Common -> Uncommon -> Rare -> ...
Right-click: Legendary -> Epic -> Rare -> ...
+2 Tier:
Left-click: Common -> Rare -> Legendary
Right-click: Legendary -> Rare -> Common
3+ Tier:
Left-click: Common -> Epic -> Legendary (since there's no higher than Legendary)
Right-click: Legendary -> Uncommon -> Common (since there's no lower than Common)