there are several 'standards' for servo placement, example, one standard for elevator and rudder servos is to place them inside the fuselage... this means you'll have short servo wire leads going to the receiver but long pushrods.. the other standard is to mount the elevator and rudder servo's very close to the elevator and rudder... much shorter pushrods means less possibility of flexing, but much longer servo leads.. this method also places the weight of the servos much further aft, meaning a greater possibility of a tail heavy airplane.
(it's very common for 3D or other highly aerobatic airplanes) Similarly you can use one aileron servo to control both ailerons OR you can use one servo per aileron.
(using this method you can combine flaps and ailerons without actually having separate flap surfaces.. you can't do that with one aileron servo)
with that one exception (flaperons) the differences are mostly physical and won't make much difference in flight characteristics due specifically to the servo's location.

I'm sure you do realise that you can mechanically change the amount of surface travel by using different holes in the servo arm and the control horn...
(using the holes closer to the pivot at the servo will cause the surface to travel LESS distance than if you used the holes further away from the servo's pivot.
the reverse is true for the control horn holes... closer to the control surface will cause the surface to travel MORE distance, further away and the surface will travel less. (more surface travel = higher load on the servo, less travel = less load on the servo))