The option for inputting large numbers is available in OXC/OXCE for well over 12 years now.
It allows to increase by 10-100 with mouse scroll button.
With the maximum setting of 100, and a single scroll movement on an average mouse, you can increase items by 700-900 at once within fraction of a second.
If this is not enough, and you need to move hundreds of thousands or millions of items at once, then there's an issue with the mod, not with the engine.