Delayed instant double jump?

On Kalos using idj (instant double jump) upair won't let you land with a second upair on the platform, delaying it just 1 or 2 frames will still get you a true combo from for instance raptor boost, but lets you continue the combo into knee. From down throw, DI down and away will of course mess this up, but this would become a lot more realistic, by adding a dash forwards before doing an idj. Doing a dash before idj does take away the period in which you can buffer the inputs, making it a lot harder, but doable.