Your client wants to be able to communicate with you? How dare they!
I'm not sure I understand why this is something you should be compensated for outside of the gig itself. Communication is a basic part of any business relationship.
You are a freelancer. Yes, that means you have the freedom to schedule your day. It does not mean, however, you can completely disappear and ignore your client's team just because you'd rather work at night. That's unprofessional.
It sounds to me more like the OP doesn't want to be peppered with 30-second bits of communication all day while he's trying to work on something else. You can't keep billing Client A while you're responding to an email from Client B, but if it's a 5-minute thing, what are you going to do, clock out and clock back in again all day?
So the communication from one client could be disruptive to other work, i.e. it could make a person lose money. If making a certain agreement with a client would cause me to lose money, it doesn't seem unreasonable to me that I would either charge for it or not agree to do it at all. In my experience, reasonable clients respect this.
_neil is right. Freckle is simple (you can track time without the hassle of creating a project) and powerful (the multiple ways you can see your data is awesome, especially the "pulse" screen) with great design (its very pretty). That said, there's more features I'd love to see, but they are constantly improving the product, so its only a matter of time.
I'm not sure I understand why this is something you should be compensated for outside of the gig itself. Communication is a basic part of any business relationship.
You are a freelancer. Yes, that means you have the freedom to schedule your day. It does not mean, however, you can completely disappear and ignore your client's team just because you'd rather work at night. That's unprofessional.