The base payment is CREDITING.

You can put it in the details(summary), in a chapter, or wherever. I'm not picky. Just be sure to add it. I work very hard to design something for you and if you don't credit, it's extremely rude and improper.

What is base payment ? 
Base payment is the nonoptional payment, which should always be done after receiving the graphic. 

The additional payment is a COMMENT.
There are two stories I ask you to read which is Immortal and/or Mated on my profile. Either one is fine by me. Just do not make it a really skimpy comment like 'really nice', 'great book'. Give it your all, even if you skim through it. I'd really appreciate it if you'd read it and gave a nice and HELPFUL critique. 

What is additional payment ?
Additional payment is a nonoptional payment, which should be completed after acceptance and before delivery.