Like £10K between lowest and highest depending on skills and experience.

What are they hoping for here? Like if they get two applicants and one is the best they can get for £20k and the other is the best they can get for £30k, which will they go for? I know there will be variables and it depends on the company etc, but like I just can't think of a scenario where this is a suitable thing to do. Maybe if they're just really unsure about the quality of applications they're gonna get so want as many as possible?