Caveat: I am not an expert, but ..

My take is that the amount of precipitation available is controlled naturally but cloud seeding can cause that precipitation to be targetted. Every time I see a big flood in, say, China or elsewhere, I suspect that someone has directed the rain there.

So, weather modification is great for causing serious floods and creating "extreme weather" that the climate scientists can point to but it is not (yet?) able to create more rain in total.