Definitely a precursor to layoffs, but they also know that not everyone will take the offer. So if you want to reduce your workforce by X%, you offer (X+Y)% the buyout. The more attractive the offer, the smaller Y needs to be.

Personnel firms have decent experience predicting the takeup of an offer, so they make predictions about how good the offer needs to be, and they try to get close, within expenses and other considerations.

If Z people take the buyout, then, after the dust settles, you layoff the remaining X-Z people.

So it is unlikely that their target reduction is 25%.