As you mention for 1), the scale is measuring the force applied on it. When "letting your mass drop" your body experiences a downward acceleration. Consequently, the force applied on the scale will be decreased. This would last only as long as your downward velocity is increasing.
Eventually you have to stop though, and as you decelerate your downward motion (or, equivalently, accelerate upward), the scales must exert a greater force on you. Consequently, the value on the scales will be higher.
Try it on a scale, from a standup position, "let your mass drop" and stop when your knees are bent. You will see your weight decreases as you drop, then increases as you slow down to finally reach its normal value.
Similarly, pushing on a table or pulling on a bar above you will lighten the force on the scale, thus decreasing your weight.