The larger size of the storage warehouse allows it to hold more items than the other types can contain and if you place another type of warehouse on it, it causes a most undesired item explosion. According to another user, this can cause a crash when inside a Factorissimo.

It also seems odd that the storage warehouse has a greater capacity when it has the exact same raw material requirements as all the other warehouses. Please either reduce its capacity to match the other types or raise theirs to keep things consistent.

Love this mod and its among the first ones I download whenever a new factorio version comes out.

I'm not against this in theory, but the storage variants were deliberately left at their old sizes when the mod was rebalanced for 0.17 for one single reason: Reducing the capacity could make items vanish.

I'd be quite happy to make all the capacities match, but I need to find a way to prevent losing warehouse contents upon upgrade first. (I don't speak for Anoyomouse, though, so he might have a different opinion.)

Then perhaps the safer option would be to increase the slots for the other variants, right?

It would be safer… but the value of 1800 wasn't chosen arbitrarily. It's a nice round number both on its own and in stacks per tile (50). 2000 stacks gives us 55 5⁄9 stacks per tile, which I don't really like, numerically or for balancing.

Maybe I should just look into making it so storage variants aren't fast-replaceable.

Another option would be to rename the current storage warehouse to "old storage warehouse (deprecated)", keep it at 2000 stacks but remove its crafting recipe. Add a new entity called storage warehouse which has 1800 storage. This will preserve the items in old saves and prevent players from making additional old storage warehouses.