Thanks for clearing that up parabellum! Doesn't sound as bad as this SQ guy put it
On the B747-400 at SQ we have the most laborious engine start procedures ever designed I think. We could have had autostart but that was a cost cutting measure.
If you proceed as per the book you cannot start the next engine until the engine being started has infact fully stabilised. After many complaints from ATCs around the world because of the time taken its now normal to start the next engine as the engine being started reaches 50% N2, still too long.
There is nothing to prevent you starting 2 engines at the same time. The result is less bleed pressure to each engine resulting in a lower N2 when fuel is introduced. The P&W didn't like this at all, and many other things too.
I'm now on the B777 with a pair of beautiful Rollers and autostart and we are all done in about 3 minutes. Heaven.