How long are you baking it? I bake my standard white bread at 425F (218-ish C.) for 25 to 30 minutes. If you're using celsius, you're dropping your temp down to 392F part-way through--why? The longer the bread's in the oven, the more the crust is going to dry out and harden up.
I've also never used olive butter before. Will it stand up to the kind of heat bread generally requires? Honestly asking here since I have no clue. It would be interesting to experiment with, though!
Another thing to try once the bread is done is to rub the top crust with a small amount of fat of some sort. If I know the bread'll be eaten in a day or two, I use butter. If it needs to last longer, I'll use a little vegetable shortening. It helps keep the top crust from getting hard and brittle.
As for the heavy issue, how heavy is heavy? Part of the charm, I think, of homemade bread is that it isn't an overly-aerated glob of cotton-wadding. It has flavor and substance, something mass-produced bread lacks.