How to Read my Fee Notice

I decided to try to figure out the fees for my 403(b) with TIAA. I’m hoping someone has looked at such a notice from them before and can explain to me.

My confusion is the fees column at the end. What is the difference between Gross .62% and the Net .45%. And does the ‘contractual waiver’ mean that there are NO fees until 9/30/2021?