TL;DR
Manual fast-inserting modules should also replace similar tiers of different module types. The goal is exchanging module types before upgrade planner and bots are usable.What?
When fast-inserting modules into an assembler or miner, you should be able to replace the existing modules, even if it's not higher tier, but just a different module type of the same tier.Same for the drop-key to replace one module, but unsure if the first or the last.
When thinking about quality, a rare prod 1 module can be better than a common prod2 module (Same prod bonus, but slower). I can fast replace the prod2 module, but not the other way around. There might be some more involved logic needed to compare stats of modules over just tiers.
The question is, if there needs to be a check, if the module is better or if you could just fast replace everything, but I guess, there's a good reason, why it only works that way?
Why?
I often want to replace efficiency modules in miners with quality modules or back. I'm still in the phase before bots, because I play with higher science multiI end up deconstructing them manually, place them again and then insert the quality modules. Same is for assembler or electric furnace lines. f.e. replacing efficiency modules in red green science with speed modules.
There's a chance I miss some ways to do it more efficiently before the bots era