I went back a bit to conserve the jetpod fuel. The moment I pick up the first fuel cell is where things are different. Even more abuse of maintaining height where that calculation error helps. 12 frames slow, but ensures I have enough fuel to get through, and I got through the tunnel saving another 8 frames, for a net loss of 4.
I abuse a 1-frame invincibility to enemy sprites called pausing the game at the exact moment. Instead of losing the pod, I bounce off the enemy harmlessly.
Hard to say how many more frames can be saved in the fuel collection. Optimizing that looks difficult.