Why did Frieza return in his first form in Resurrection 'F'?

In Dragon Ball Z: Resurrection 'F' (2015), Frieza is brought back from chopped-up pieces of his Mecha Frieza body, yet he comes out of the revival machine in his first form. The reason is that the machine that rebuilt him only had data for that first form, and the clues that explain why are in the original Dragon Ball manga and Dragon Ball Z, not in Resurrection 'F' itself.

Nobody's talked about this, and I haven't seen this explanation anywhere online.

Frieza died as Mecha Frieza but returned in his first form

In Resurrection 'F', Sorbet brings Frieza back to life with the Dragon Balls. Frieza's body is in pieces, and it's him in his Mecha Frieza form. That was the last form we saw him take while he was physically alive. Mecha Frieza is like a taped-together version of his final form.

But when Frieza's forces put those body parts into their machine, it somehow brought him back in his first form. So how did Frieza go from the chopped-up pieces of a rebuilt final form to his first form again?

The original manga reveals Frieza's final form is his true birth form

In the original Dragon Ball Z anime and the Dragon Ball manga, Frieza reveals that his final form, his fourth form, the one he used to fight Super Saiyan Goku, is his true birth form. The first form we see in the hover chair is a form Frieza created to suppress his power. The same goes for his second and third forms.

Frieza also reveals in the original manga that nobody outside his own family had ever seen his final form, including his own minions. That detail is the key to everything that follows.

Sorbet was nowhere near Namek or Mecha Frieza

During the events of the Frieza saga, Sorbet and his section of the Frieza empire were elsewhere in the universe, doing something else during that battle. When Goku defeated Frieza and King Cold came to find the body and rebuild him into Mecha Frieza, Sorbet was again nowhere to be found.

At some point, Sorbet was informed about what happened, including that they went to Earth. But he wasn't there for any of those events, so he never saw Frieza's other forms for himself.

The Resurrection 'F' machine works like a Dragon Ball 3D printer

By the time Resurrection 'F' takes place, a number of years had passed since the battle on Namek. Because of that, Frieza's empire has definitely made vast improvements in technology. It now has the device we see in the film, which can put body parts back together.

The way the film shows this machine rebuilding Frieza from the deceased Mecha Frieza, it seems to be a fantasy Dragon Ball version of how a 3D printer works. With a real 3D printer, you have to program it, and it takes particles and puts them together to create a material object. Here, they took Frieza's chopped-up body parts and threw him in there. Apparently he was still alive somehow, because you see his eye blink. The machine was able to reconstruct him.

The machine only had data for Frieza's first form

So why the first form? Frieza's empire, and especially Sorbet's part of it, only had data for Frieza's first form. They had never seen his other transformations. When you program a 3D printer, you have to give it the correct data, and Sorbet's forces never had any code or data for that final form.

The machine did the best it could and rebuilt Frieza in the only form it was familiar with, his first form. That's why he comes back that way despite being Mecha Frieza only a few scenes before. Frieza himself knew how to go back into his final form once he had his new body, but the computer didn't know how to do it. They did not have enough data to create final form Frieza, and to me, "it actually makes perfect sense."