It’s “. . . works only if,” not “. . . only works if.” The position of “only” in a sentence can change its meaning dramatically. Witness:Only I poked him in his eye with my stick.I only poked him in his eye with my stick.I poked only him in his eye with my stick.I poked him only in his eye with my stick.I poked him in his only eye with my stick.I poked him in his eye only with my stick.I poked him in his eye with my only stick.I poked him in his eye with my stick only.
It’s “. . . works only if,” not “. . . only works if.” The position of “only” in a sentence can change its meaning dramatically. Witness:Only I poked him in his eye with my stick.I only poked him in his eye with my stick.I poked only him in his eye with my stick.I poked him only in his eye with my stick.I poked him in his only eye with my stick.I poked him in his eye only with my stick.I poked him in his eye with my only stick.I poked him in his eye with my stick only.