This is a daft question but it's from the centre line of the clamp to the centre of the seatpost at the top of the seatpost?

I've got a new bike (Focus Cayo) and despite the effective toptube being shorter it feels stretched compared to my old bike. The stem is longer and I knew that so was prepared to buy a slightly shorter one. But there is also more layback on the post. 35mm as measured above whereas my old one is 25mm. Is there any reason not to have 0mm layback on a road bike?