Does oven spring differ between white and sourdough breads?

In my experience, there’s no reason to assume that it’s because of the dough type. Both can get good oven spring and ears. Due to the way the yeasts and bacteria in a sourdough work, I find sourdough breads to be more finicky than pure yeast ones.They can get softer and flatten during the final rest, where yeast-only breads typically keep the surface tension and shape better.

I recommend you take a closer look at

• Proofing time:
  Aim for slightly under instead of fully or even slightly over. Note that the margin of error is smaller for yeast breads, especially if you use the “fast” recipes with a rather high amount of yeast.
• Shaping:
  A good surface tension helps the slashes to open better.
• Slashing technique:
  Flat, almost horizontal cuts with a swift blade gives the coveted ears, vertical cuts just open up like a blossom unfolding.
• Humidity during the initial phase:
  Don’t just spritz a bit of water in the oven and forget the “place a bowl in the oven” recommendations, that won’t give you a sufficient humidity level in the oven. You need quite a bit of thermal mass (some place a tray full of stainless steel nuts and bolts in the oven) and enough water that you should get to evaporate in one go. I usually splash a scant cup of water just off the boil right into the oven when I have just placed the loaf. (Careful, that’s a lot of steam and you can hurt yourself if you aren’t quick. Some ovens even can warp due to thermal shock, but I can live with that.) Open the oven door for a minute when the first phase is done and your oven spring has happened, usually by the time you lower the heat. Or bake in a Dutch oven.