I think there's a larger question here. From my (non-TKD experience), the movements in forms are movements you can fight with, and sparring is practicing fighting. Therefore, you can use those movements when you spar.
If for whatever reason you aren't, you have to figure out: Is it a systemic issue (e.g. is the system teaching unrealistic forms, and/or unrealistic sparring rules), a teaching issue (e.g. is the teacher not teaching you the movements properly/their purposes, and/or not encouraging you to try them out in sparring), or is it a personal issue (e.g. are you not attempting those movements in sparring, and instead are focusing on other non-form techniques, or just going by instinct)?
I don't know TKD, your teacher/dojang, or you so I can't answer which of the three it is, but you should probably make sure you understand where the issue is first.