I am not quite sure of the exact problem, is this what you are doing:?
Import 59.94 FPS footage (it’s progressive 60P, not 59.94i with fields)
Create a comp from that at 59.94, set the duration to proper length
Import that comp in main comp, set main comp to 24P
apply twixtor there, set Input FPS to 59.94 inside Twixtor
render in AE 24P
import footage in Premiere 24P
If it looks good out of AE, should be good when importing in Premiere
Is this what you are doing?
Pierre