Problem with llSetPos

Can anyone help me with this problem?
i made a script for a chair when you touch it the chair goes to about 50m high and then eject the person and then the chair goes back to home position.

The script works except the part when the chair goes back to home position.
Sometimes it goes back but often the chair goes back to about 36m high and i don't understand why.

First i tried to set home position with llGetPos and later hard coded the home position.

i have also a 2e question:
Sometimes the camera follows the avatar when it goes up and other times the camera stays at home position. does any one now how i can change it that the camera always follows the avatar?

Thanks

<CODE>
vector Home=<16.0, 20.0, 21.3>;
vector Position;
float Height;
key Av;

default
{
state_entry()
{
//Home=llGetPos();
llSetStatus(STATUS_PHYSICS, FALSE);
llSitTarget(<0.07, 0.2, -0.25>, <0.0, 0.0, 0.85, 1.0>;
}

touch_start(integer total_number)
{
llSetStatus(STATUS_PHYSICS, TRUE);
llSetBuoyancy(1.2);
llSetTimerEvent(1.0);
}

changed(integer change)
{
if (change & CHANGED_LINK)
{
if (llAvatarOnSitTarget() != NULL_KEY)
{
Av=llAvatarOnSitTarget();
}
}
}

timer()
{
Position=llGetPos();
Height=Position.z;

if (Height > 50.0)
{

llUnSit(Av);
llSetStatus(STATUS_PHYSICS, FALSE);
llSleep(2.0);
llSetPos(Home);
llSetTimerEvent(0);
}
}
}

llSetPos moves a maximum of 10m on any axis per call.

You need to call it multiple times or use WarpPos instead.

Thanks Talarus didn't know that.

The camera will follow the avatar up if the focus is set on the avatar (alt left clicking the avatar before going up). If the focus is on something else, the cam won't follow. You'll need to ask for permission to take cam controls, then force the cam focus, or force mouselook to solve your problem.

Thanks Johan and Talarus for your answer.
I solved it with warpPos but have to look further in cam control or mouselook.