In the case of a motion made to amend an amendment, to stay within scope means that the suggested change to the amendment cannot propose a change greater than what is currently being considered. In other words, scope refers to a range of options that falls between the current situation (what is) and what is proposed (what will be if the proposal is adopted). As an easy example, GSUSA is currently divided into 6 geographical regions. A proposal is made to disband regions entirely. Therefore the “range” between “what is” and “what is being proposed” is 6 regions (“what is”) and 0 regions (“what is proposed”). An amendment to have 10 regions would be “out of scope” (and ruled out of order) because it does not fall within the current and proposed range. An amendment to have 5 regions instead of 6 would be “within scope.” Scope is easy when numbers are involved, but determining scope on other issues can be tricky – then it’s time to consult a parliamentarian! Scope allows a delegation to study the implications of the range between “what is” and “what would be” if the proposal is adopted. The idea of amendments having to be in scope is to protect the organization from making drastic changes that no one has had the opportunity to study at all.
Source: Robert’s Rules, 11th edition pg. 307