Holes in loaves

I'm not sure why . . . or whether it's universally the case . . . but I seem to leave far smaller holes in the bottoms of white and French loaves than either wholegrain or wholemeal loaves.

I have baked the last 3-4 whites on a darker-crust setting, and for some reason, the mixing paddle pops out with a drama.

At this rate, I am only winding up with one damaged slice instead of the 2-3 I encounter on heavier breads.

I'll keep you all posted!