not a bad idea for domestic flights where you´re starting the engine after 30 or 40 minutes of last shutdown and residual EGT is normally high. Being a First officer and having attempted to do that (and briefed so) I was told to stick to what the manual or airline policy says...
seems that they wanted to go home quickly and couldn´t wait 20 more secs total.
What I was allowed to do a few times was to reposition the a/c for a no tailwind start.