An alternative workflow that I think would work if you need to timeremap audio as well (AE only)
– Select clip with TimeRemapping Speed applied in Premiere
– Right Click Make New AE Comp
– IN AE select clip and Right-Click PreCompose
– Double click to enter Precomp, Apply Twixtor with default values
– Return to main comp and render
As you see Timeremapping is the inverse of Twixtor speed
Pierre