Hi Vinh,
I think that you need to ask Support via the https://support.smartbear.com/testcomplete/message/ form for official but not guessed answer.
To my level of knowledge, any script language runtime always loads and 'precompiles' script code before execution. This is functionality and architecture of script language runtime but not something that is specific to TestComplete itself.
Thus I think that all statically available script code will be loaded before execution start regardless of the way you organize it.
