The book isn't well written, but even so, I think the answer here is fully and adequately provided, as follows, unless you are willing to willfully attempt to circumvent the spirit of the rules just to try to gain an edge - and even then, any APA official with an understanding of the intent of the rules should see through and bar against that effort:
The key word here is "majority." I'm going to assume we can all agree that majority can be defined as being greater than 50%, limiting the number of Regular Shooting Cues (hereafter "RSC") for a player to a single cue to be represented by a player as the cue they choose to use for the majority of shots because any other cue is, by definition, limited to being one they would use for less than 50%, i.e. a minority, of shots.
Therefore, any cue that is not the one you are using for the majority of your shots does not meet the definition of RSC as that definition applies to you, and does not have the freedom of eligibility of use for jump or masse shots enjoyed by your actual RSC.
"Majority" makes it clear cut - someone can't sustain the argument that they would use two different cues, each for a majority of shots, in a game. One has to win out, and that one has to be the only one allowed for those restricted shots.