They almost certainly aren't the same series of shares, but that in and of itself isn't a reason to expect them to be worth less. Usually preferred shares have additional rights (e.g., preferred share holders will get returned their original cost or some guaranteed return before common shareholders get any returns).
Some have features that get them some incremental value over time (e.g., a 10% return paid through additional ownership over time), but this would differ wildly depending on funding round, investor, etc.
If the business keeps growing and the whole equity cap table is "in the money," his shares could probably be close to this estimated value.
Caveat: you can go totally nuts with complicated share structures, so this could not at all be the case for Domo.