Roman numbers

In Russia, Roman numbers are used even by not very literate people. One example.
The log house needs to be moved to a new location. Before disassembling it, the logs are numbered in Roman, not Arabic numbers.

Do you know why?

Choose please the correct answer!

1 The carpenter wants to show his high culture - knowledge of antiquity!

2 The carpenter cannot count, but he has a clock with Roman numerals on his left hand. He looks at them and numbers the logs.

3 

People who are assembling this house in a new place may not know Roman numbers. But such a program will help them!

But this program has a small defect. Can you find it and fix it?