It has been discussed a numerous times (like the topic in the link below) and several active Rhino users, myself included, think that it would be best to add a new option in Rhino to choose whether the last remembered value should be read from the manual moving of Gumball or the last typed value with the keyboard. Remembering the last distance after a manual dragging is very useful while Grid snap is turned on so that the same value could be easily repeated; however, some people prefer id Rhino remembers only the keyboard input. Both behaviours have their own strength.