Hi Jayesh,
Yes you are totally right, it is whenever a change is done in the delivery template itself.
If you need to raise new delivery on some other circumstances, you must achieve it with specific code in the workflow (as Message Center does, for example, for having different delivery execution folders per month).
Take care, if your delivery template has customization blocks, if you change the custom block content it is not the same.
Regards
J-Serge