Possessives and Attributives

Q. I’m working on a legal document in which the defined term “Approved Services” could mean one service or more than one. When I am referencing the “Approved Services’ signal” throughout an agreement, how can either the singular or the plural possessive of the word be written? “Approved Service(’)s(’)” seems right to me, since the apostrophe is what can be used for either meaning, but it looks weird. The author of the document uses “Approved Service(s)’ signals” throughout, but this doesn’t show that the apostrophe is what is in question based on either possible usage.

A. Only a legal office could get into such a mess over something like this. Just use the attributive: Approved Services signal. Those who are involved in a single service will probably be able to figure out that this applies.