If you include the steps, then yes its 5x4. But if you include the steps in the program, it's 5x5.
Ide like to weigh in on something, this is both accurate an inaccurate, i cant see what is going wrong here but the house model is off.
Linked is a in game and in designer screenshot and things dont line up where they should / look very out. I do think the house model is to blame but I am willing to be proven wrong
https://imgur.com/HjJn7LP
Your house model is wrong, I did the ACNH science and by that i mean i drew a grid and your house model is too big https://imgur.com/a/T4oPN6d
I can walk behind my house so there must be a layer behind but then the house in the app is one too far foward
Do not use the front as reference as i miss placed the land, please go from back of the house towards the camera