Yes, you understand correctly. The minimum amount to withdraw is an amount that would cost 1000 USD to buy. When withdrawing that amount, you would get 350 USD
3.B “Minimum of 100,000 earned Robux in your account. In order to protect against money laundering and comply with applicable law, we limit all Cash Outs to "earned" Robux. Robux are considered "earned" if you receive them by receiving payments from a bona fide third party transaction through the Services for (a) virtual items (such as clothing for an avatar) that you created or (b) virtual things in your game or for your game or experience. This means that Robux acquired in other ways (e.g., receiving Robux as part of a membership plan or referral bonus, a purchase of Robux or gift card, or trading/selling virtual goods that you did not create) are not considered "earned". We will determine how much you are eligible to Cash Out by totaling the amount of Robux earned (over the lifetime of the account) and subtracting the amounts previously paid out to you through DevEx;”
Also note that there is a comment in the video that you need to be careful how you spend your Robux for buying development, because if you are not then a cut gets taken, which maybe relates to 3B for the person you are paying?
