Not sure about that, SSDs historically have followed base-2 sizes (think of it as a legacy from their memory-based origins). What does happen in SSDs is that you have overprovisioned models that hide a few % of their total size, so instead of a 128GB SSD you get a 120GB one, with 8GB "hidden" from you that the SSD uses to handle wear leveling and garbage collection algorithms to keep it performing nicely for a longer period of time.
Sounds like an urban legend. How likely is it that the optimal amount over-provisioning just so happens to match the gap between power-ten and power-two size conventions?
More recently you'd have, say, a 512GB SSD with 512GiB of flash so for usable space they're using the same base 10 units as hard disks. And yes, the difference in units happens to be enough overprovisioning for adequate performance.