The manufacturer's price is a fixed rate per model and type of damage. It is the same everywhere, no matter how much work your device actually takes.
That rate covers more than the part and the working time. In the authorised network, spare parts, tools and every work step are set by the manufacturer, and usually the whole assembly is replaced. With a cracked screen, that is the complete unit with everything attached to it, even if only the glass is broken. If the device has to go to a repair centre for this, shipping and waiting time come on top.
So is the higher price justified? Partly, yes. You pay for a process that is the same everywhere, and in some cases you get a replacement device instead of a repair. But you don't automatically pay for a better repair of your damage.
With us, the price depends on what is really broken on your device. We replace the individual part, tell you the price after the free diagnosis, and only start once you have agreed. A repair with us is cheaper than with the manufacturer.