Here is a review of the EX Pro that may answer your question about user over provisioning (page 2):
Factory and user over provisioning space are two different things. Consumer SSDs do not have much factory OP space in order to keep the price down.
Business/Enterprise oriented SSDs always have more factory OP space, generally that is ~50% of the specified user space of the SSD.
While a 512GB and 480GB SSD actually have the same amount of NAND (512GiB), the 30GB difference between the two is the difference in factory OP space, working in GB rather than GiB for this example.
Whether or not user OP space is truly useful depends on the way the user actually uses the SSD. Most of us never stress our SSDs in the way that review performs consistency testing with and without any extra user OP space.
I usually set aside ~15% of a SSD’s capacity as user OP space, but I cannot tell you if it really helps, given my usage profile.
