Control plan中只用Special characteristic可以吗?

APQP手册中有这样一句话"All Speciall Characteristics must be listed on the Control Plan. In addition, the manufacturer may list other product Characteristics for which process controls are routinely tracked during normal operations."
我的理解是"may"表示后面的是可选项, 即Control plan中可以包括其它Characteristics, 也可以不包括, 但识别出的Special Characteristics是必须要包括在内的. 换句话说, Special characteristics是Control plan的最基本要求. 对否?