I don't think 20 turns is that much, but others can probably give you a better answer. 

My diastema appeared after 35 turns at 1 turn per day. 20 turns is still early for when you might expect the split. The bleeding gums around your molars might be something to ask your orthodontist about. Do the molars appear to be tipping?

@apollo a bit, maybe. At least I can't tell at the mirror. I noticed a very small gap opening between my incisors, but nothing I can call a diastema yet. Did you get any signs the treatment was working?

Posted by: @serbian

@apollo a bit, maybe. At least I can't tell at the mirror. I noticed a very small gap opening between my incisors, but nothing I can call a diastema yet. Did you get any signs the treatment was working?

I had hairline gaps or opening of the contacts between all of my front teeth before the midline diastema eventually popped open more than a millimeter with some dull pain within the span of a couple hours. 

@apollo it looks like my appliance reached the maximum expansion (9mm), but no diastema yet, only a barely noticeable gap. It means only my tooth moved? I'm thinking of asking my orthodontist to replace the current appliance with a 11mm one, do you think it could help? I apologize for the bad quality of the picture.

Posted by: @serbian

@apollo it looks like my appliance reached the maximum expansion (9mm), but no diastema yet, only a barely noticeable gap. It means only my tooth moved? I'm thinking of asking my orthodontist to replace the current appliance with a 11mm one, do you think it could help? I apologize for the bad quality of the picture.

 

Your appliance has a different structure than an MSE. It doesn't even look like any kind of MARPE as I can't see any TADs anchoring it into the bone. Is it possible you just have a hyrax expander? If that's the case and it doesn't have TADs implanted into the bone, then it's not surprising that the midpalatal suture didn't separate. The expansion would be from a combination of dental movement and alveolar bending or remodeling. If I'm wrong and your appliance is some kind of MARPE with TADs that aren't visible in the picture, then maybe they didn't have good placement with bicortical engagement resulting in screw drag. If you decide to go for another round of expansion, I would insist on a bone-anchored expander with CBCT planning to ensure stable, bicortical placement. It's possible that your orthodontist isn't trained in such techniques. Most aren't.