Right, you want to use as low a #lpc as you can get away with. However, load increase depends upon what is happening in the code, try running these three snippets in turn while monitoring your cpu usage with each:
set #lpc 200
set %a 1
while #true
{
set %a %a + 1
}
set #lpc 200
set %a 1
while #true
{
finditem *
set %a %a + 1
}
set #lpc 200
set %a 1
while #true
{
finditem *
set %a %a + 1
sleep 10
}
The reason I cranked up #lpc in your script was to run boiler plate (pure data manipulation, menu, and control flow) code as quickly as possible in order to increase UI responsiveness and to measure how long craft gumps disappeared when an item was created. You can set it lower if it is causing problems, however most simple scripts tend spend a majority of their time waiting to do something cyclical, and such waits tend to break up the cpu utilization into bursts, regardless of the #lpc setting.