Sure, the ammunition are sitting next to each other in a carousel. If the carousel is full, shrapnels from penetrating ammunition will hit a live one inevitably and they all go off. By leaving space between them you'll decrease the chance of getting a hit on them. Most of the ammunition are better covered than others in the carusel as there is much more metal on top (eg where the load mechanism is).
You are right though that hitting a live 125mm round ruins your day, but the turret doesn't turn into a space craft so there is some chance of survival against zero chance with turret removal.
I have pictures of a T72 turret that was shot at with 125mm 3BM15 armor piercing shots. It didn't penetrate the cast turret with a direct hit, but penetrated via the gun cover and via the turret ring. Entering the turret it basically broke a lot of sights and other equipment and hitting the back of the turret. The generated shrapnels in the rear of the turret in both instances of armor penetration was calculated to cause full cartouch to explode in chain and in practice blowing the turret off (what we've seen in videos recently, very spectacular).
By decreasing the amount of rounds in the cartouch you'll decrease the amount of exposed ammunition. Or that is the theory at least which was presented by a Russian tank crew member in a Russian interview a few weeks back. I've no knowledge how it has worked out for them as the turret is a death trap anyway once gets a direct hit from a javelin. But at least there will be something left to send to the mourning family.
Edit: nutloose is pretty much spot on with his faster response.