Haha - no, not at all.
Actually, this is possible with both the API and POST forms. With the API you just do a bit of logic in the PHP to specify a different redirect URL - nothing special there. But with POST forms, you need to include a hidden field containing the URL you want to redirect to. This will override whatever is defined as the Redirect URL within Form Tools.
Hope this helps!
- Ben

Actually, this is possible with both the API and POST forms. With the API you just do a bit of logic in the PHP to specify a different redirect URL - nothing special there. But with POST forms, you need to include a hidden field containing the URL you want to redirect to. This will override whatever is defined as the Redirect URL within Form Tools.
Code:
<input type="hidden" name="form_tools_redirect_url" value="http://yoursite.com" />
Hope this helps!
- Ben