Hii @crypto.piotr,
This is a good question, The moment you exit the pool you will receive the 1000BUSD that were locked during the staking period.
The amount of tokens you have at the end of the day depends on the apr(annual percentage rate) throughout the day. The apr is based on how many transactions your tokens have validated throughout the day. The more tokens locked the more the chance of gaining rewards. I am not sure how the price of RBS token will affect the current apr.

The current apr for BUSD is: