I've written about why sheet cakes, or kitchen cakes as some people call them, aren't always a good option. It's a subject that's worth revisiting occasionally, especially since magazines and websites continue to tell brides that sheet cakes will save them money.
Personally, I charge pretty much the same for a sheet cake that would go with a wedding cake as I would for the wedding cake. If it's a matter of baking a four-tiered cake, or a four-tiered cake plus a sheet cake, that means I'm doing extra baking. So that's extra time. And that costs me, so it will also cost the bride. So I don't recommend extra sheet cakes.
Anyway, I listed a bunch of reasons why I don't like sheet cakes in the original article. I recently heard another reason that wasn't on my radar, but maybe should be.
A baker I know made a sheet cake that she delivered to the kitchen after she set up the wedding cake. The planner later went to get the cake for the bride's parents since it wasn't needed for the guests, but the kitchen staff said that the baker had told them that it was for them, so they ate it.
This obviously wasn't what she said, and the planner knew it, so she started to press the issue. She let the baker know about it, and the baker called the venue to see what had happened. After a lot of back and forth the baker and planner had gotten nowhere. The last thing they heard was the owner and catering manager at the venue basically telling them that it never happened, and that they were lying.
So the bride ended up paying for a sheet cake that not only wasn't even needed in the first place, but was also stolen by someone. When cake is out of sight in the kitchen, there's a good chance that it will be forgotten. On the other hand, if they cut and plate it ahead of time there's a good chance that it will dry out. So you lose both ways.
I'd suggest that you get one wedding cake that includes all of the servings that you need, and skip the sheet cakes. You'll avoid the possibility of dried out, meat flavor-infused, cold/stale tasting, or stolen cake. Which is always good to avoid.
Kara Buntin owns A Cake To Remember LLC, custom wedding cakes in Richmond VA