Price Sync

I am trying to understand Price Sync. I add products and then manually set prices. If I turn on price sync, as long as the price does not change on supplier, the price will remain what I set it as? Is this correct?

However, if I add a product that is on sale, the sales end, and the price increase, it will update the price to whatever it is normally, when not on sale, and then add whatever I set in rules?

Is this correct or am I totally missing it?

Thx.