Is this an issue?

[bobkreid]

Aye, the issue is as Matt stated: *All QB64 subs and functions come with some built in overhead.*

In this case, the function you produce is basically:

Function Add (v1, v2)
  Step 1: Check for errors.  If any, send error message.  Pause.
  Step 2: Check for break/exit conditions.  Ctrl-C, or Red X in top right of Window.  Quit if clicked.
  Step 3: Allocate temp variable.
  Step 4: Add v1 + v2, assign to temp
  Step 5: Assign temp to Add for return value
  Step 6: Cleanup temp variables
END FUNCTION

Compared to a base C function of:

Function Add (v1, v2)
    Return v1 + v2
END FUNCTION

If necessary, you can remove some of that overhead with $CHECKING:OFF before your Function, but be aware that it'll disable the check for exit conditions and error reporting, if you do so.  (And remember to turn $Checking:On after the Function.)

But I think the example above easily explains why you're seeing the results you're seeing here. 

Thank you Sam, hope all is going well for you.  A lot more is going on in QB64 than I imagined and will take that into account in the future when I see these types of things.  Thank you for helping a noob with this.