Your current top tube, seat tube and head tube only give scratch the surface of bike fitting. Your proportions, seat tube angle, BB drop and frame stack are also important factors to getting a great fig.
Caveat aside, 10mm in a bike's reach is relatively easy difference to accommodate by changing:
- stack height (spacers or flipping the stem)
- shorter reach road bars
- shorter stem
- even choice of shifter/brakes brand can tighten up the reach a bit
I personally prefer playing with a shorter reach bar and stack height before going to a shorter stem. Depending on how much drop you currently have on your road bar, a higher stack may be all that is required. If it you currently have a large amount of drop on the road bike, riding a bike with more stack - less drop on the handle bars - will require more reach to feel comfortable (otherwise you end up feeling cramped). You can draw an imaginary arc by holding your arms constant and pivoting on hips to see how much reach gain you may want for a more upright position. At some point of course if the stack is too high (ridiculously high) you will again want a shorter reach.
Again this is personal preference, but a higher stack also makes sense on a cyclocross bikes (and training bikes). The bike is more manageable on rough terrain and easier to mount/dismount with a bit more stack. It is interesting that so many cross bikes being sold now are so slammed (in terms of frame stack), I suspect this is so they can "look right" when being marketed as a cross-over bike for those that want a winter or training road bike and not necessarily a cyclocross only bike.