Underground Vault Enhanced Patch
This mod cuts the upgrade cost of all Underground Vaults in half. Building a new level also takes half the time. Starting storage space is increased by 2 to 3 times, and the time to access items is now only 25% of what it was.
The main goal is to make the vaults more useful when playing with other deep storage mods, without making them too cheap or letting you store huge amounts of stuff for free.
The shorter access time makes it easier to store items in vaults, which reduces the number of item stacks on the map and helps slow down lategame savefile lag.
This should also work with older versions of Underground Vault. If some vaults are missing in the old version, you might see a few errors in the log when applying the patch. Other than that, there shouldn't be any problems.