Random is your answer to both questions. The engine will always stop when one of the pistons reaches top dead center in the firing position, just physics, so that the chances of stopping in the same place will be 1 in 5.

The starter solenoid, when engaged, pulls the starter gear into contact with the flywheel so the starter motor turns the engine. The gear is quite small, I don't recall the number of teeth, but at least a dozen, so the odds ar greater than 1 in 12.

When the starter solenoid goes bad and no longer engages forcefully, it can cause the gears to slip on the flywheel, damaging the teeth on the flywheel. Because of the 1 in 5 chance that the flywheel is in the same position, the same teeth can again be damaged repeatedly. This is why the starter needs to be replaced when you hear repeated grinding or high pitched noises when the starter is engaged.

Make sense?

Klaus

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Proud owner of a 220S. If I had more room, I would have more Volvos.