Sourdough

I was wondering if the timing of folds during bulk fermentation might affect oven spring. I made Ken Forkish's Walnut Levain Bread today and I was a bit disappointed that my loaves didn't get the usual oven spring that I have been getting with most of Forkish's recipes. I had to rush the folding so instead of having 20 to 30 minutes between the first fold and the second one, there was only about 10 minutes. The next fold was about 20 minutes later. The crust was awesome as usual and the crumb nice and springy with a much airier texture than I expected.