Steel bits need to be very sharp to do their job. In fact, unless you set a depth gauge just barely through the metal, you'll wreck the cutting edge with every hole when you contact concrete and need to resharpen.
Concrete bits create holes by pounding and disintegrating the material. They have cutting edges, but that's mostly to focus the impact and clear debris. They become dull over time as well, but it doesn't dramatically affect their performance.
Ideally you'll drill your plates in advance, then use them as guides for drilling the concrete. Herb Guy offers some good advice on that note: "Try to find a local welding, ironworks or machine shop. They can punch or drill those holes for faster and cheaper than you ever will and make the S/S plate hole's ø 1/8” larger so the hammer drill tip and anchor shields/wedges pass through."
Otherwise, I suggest having several of each type of bit on hand. The steel bits will need time to cool after several holes (unless you lubricate with oil), so you'll want to rotate them, and the concrete bits occasionally throw their carbide teeth.