if you have selected F30 then you set F30 green bug. However, the trap is Vref 40 + wind additives could be higher than F30. So Vapp would be set. It is more comfortable and better for the trim changes to sequence F15 - F25 - F40. It's less strenuous if going F15 - Vref30, but if landing F40 it can be a trim strain going F15 - F40 in one step.