Hello,
From what I read, someone who sells btc sometimes has trouble receiving the fiats in its bank account. If the sum is large, the bank turns on all its red lights.
These sets of people often or alway uses a business and a company account to sell out their bitcoin to fiat in larger quantities.
However, there are different types of bank account which i think for you to deposit a higher amount of money you must need current or company account to send out money instead of using a savings or students account to pull out large amount of money. Company account doesn't go into questioning that much and are free to transfer and receive a higher amount.