you actually got that the wrong way around.
When you sheet in using the long de power line you are 'de powering' the kite. if you need to take more weight off the kite you would let it out slightly.
Hi I wrote taking weight off the board, not the kite. I love this bar and also when riding toeside on a waveboard it helps not to lose your position on the board, instead of sheeting out with the bar you can just sheet in with the depower and get further tucked into the wave.