Your for() loops are not the same. In the second one, you count down from 180 to 0. When that is done, pos will be -1 so the test if if(pos==180) will NEVER be true.
Much easier to
- turn on LED
- execute for() loop from 0..180
- turn off first LED, turn on second LED
- execute for() loop from 180..0
No additional if() statements required.
As for the 4 hour delay, look at the Blink Without Delay example in the IDE (File->examples->02.Digital->Blink WIthout Delay) to learn how to track elapsed time without blocking other code from running.