Q. Does Microsoft VB Classic support developer defined function and sub overloading?

A. No, not at all. Some developers like to pass in an array and then handle the array for a pseudo technique but that's not really overloading.

About Overloading
Types of overloading include method overloading and operator overloading. Method Overloading is where different functions with the same name are invoked based on the data types of the parameters passed or the number of parameters. Method overloading is a type of polymorphism and is also known as Parametric Polymorphism. Operater Overloading allows an operator to behave differently based on the types of values used. For example, in some languages the + operator is used both to add numbers and to concatenate strings. Custom operator overloading is sometimes referred to as ad-hoc polymorphism.