They mention repeatedly the amount raised, I didn't see where it said at what valuation. If they were left with 75% of the company, that would have been a nice seed round. If they were left with 20% of the company, not so much.
My guess would be the seed investors have terms that are essentially like having 20-30% of the current company. Selling an effective majority stake (or anything near it) in a 'seed' round isn't a typical valley thing.