Question: Running mini pools using rocketpool

Hey and thank you for your help.

Currently staking eth( getting around 4% return via lido/ rocketpool) considering to purchase a set up in order to run nodes by using rocketpool in order to achieve higher (7%) returns. What I am worried about is the 10% Collateral I am required to post in RPL. What happens if there is a gap in the value between ETH and RPL compared to the time I made my initial deposits and my once correctly deposited RPL now no longer reflect 10% of the ETH value, do I need to purchase more RPL In order to maintain a 10% balance, or does it only matter in the moment of depositing?