With how much anticipation can I usually reserve a Sharehouse?

I tried looking for info on this in the subreddit but all I could find was reviews for sharehouses and so on. I’m going to Japan on April 1st as a language student and I was looking to rent a private room in an Oakhouse sharehouse in Yokohama but I was told I could only make a reservation 10 days prior to my arrival and if I wanted to reserve with more anticipation, I had to pay the time that exceeded 10 days.

I guess I have 2 questions, is this common throughout most Sharehouses? Or was this a case of only Oakhouse policy or maybe even that particular place?

My second question, do people usually pay in advance even if they haven’t started living in their Sharehouse?

I am a bit scared that waiting up to 10 days before my arrival might make me lose out on several rent opportunities that I could’ve otherwise had if I had known better. I would appreciate hearing about your experiences and if you have any tips regarding this.