It's because you wrote your Zorro script in Lite-C.
numbers or constant expressions containing a decimal point (123.456) are treated as float with 7 significant digits.
https://zorro-project.com/manual/en/aarray.htmZorro also supports C++ scripting, where you will not have to deal with the eccentricities of Lite-C and its compiler.
https://zorro-project.com/manual/en/dlls.htm