I don't think a jump like you're doing is enough to make that gap. You'll need a little more momentum, which you can get by jumping from the left side of the platform instead of the right.
This video (6:30 in) shows you the way I find most consistent to do it. iirc it's way easier with 2 jump buttons (one button for each jump, and don't let go of the first button until after you get the jump).