That's somewhat odd. What does mysub{} do?
Deparse is actually returning the interpreter's version of your code to you, so it will have some amount of inlining performed and a few other things specific to the state of your code when you deparsed it. In other words, your code will be slightly optimized and you should beware of early optimization. Perhaps I should have phrased my earlier statement:
The deparser, when it works, returns (more or less) your code in a pretty format.