That sounds pretty dubious. Do you actually have any black and white offer with specific higher salary numbers? Is this a small sized boutique consultancy with 1 founder + few consultant type?

I cannot imagine any sizable company out there would make this sort of open cheque promise to a normal fresh grad. This sort of flippancy makes me wonder how much of their job description is even real in the first place.

Just be careful as your company B looks suspicious to me. From experience, I am always cautious of companies that seem to be selling themselves to me instead of the other way round. Real good companies won't do that because they don't need to.