Their fees are fixed, they do not impose deposit fees.
It's true that they don't charge any fee for deposits.
In fact, they (and almost all other exchanges I know) waste a lot of money for consolidation of deposits and instead charge a high withdrawal fee.
Below is the latest transaction they made for consolidation of deposits.
9b0f29a7e27d448c8b9f83a79696c0b18bd4bdb8144ebfc082b609ccda962596They made the transaction with 84 sat/vbyte.
This transaction could be made on the weekends with less than 10 sat/vbyte or even less. I don't think they have to hurry for consolidation of funds.