I would assume that's it's fine to take it anytime of the day, so long as that it's usually at the same time. For me, I take dutasteride every morning, on an empty stomache. I read some sort of study on dutasteride saying that taking dutasteride (and this is probably the same for finasteride) doesn't fully absorb when taken with food. I believe that 15% less of the dosage was absorbed, but that's just off the top of my head. I'd have to find that website again.
But anyway, sorry about that tangent. I just think it's best if you take it at around the sime time of the day. My two cents.