unfortunately this guide, as many other ones, doesn't explain anything if the seed was too long
I'm still waiting for a damned IOTA dev reply to this thread, maybe after 1 year or 2 I will find somebody helping me to recover my IOTA lost-in-sleeping balance
You would know only if you have read the guide properly and did your due diligence. Refer to Point no. 4, they have details of issues faced and resolution for same. Point 4 Sub Item 1 should have answer to your problem.