Index time is controlled by eBay and there is nothing Auctiva can do to improve it.
Scheduling your item with eBay does not affect the index time as far as I'm aware. I see just as man people on eBay message boards complaining about this, actually probably more. It all depends on your items and the time you list them how fast they index. I've actually seen a ton of posts on eBay's boards saying to use Auctiva because if you list with us your items index faster, which isn't true. But it goes to show you that people that list with eBay directly think we list faster. Everyone is just wanting their items to index faster, whether you list with us or eBay.
It's my opinion that the longer index times are caused by eBays new measures to combat fraud. Since fraud is a bigger problem than index time the index times don't bother me as much. Left on the course they were on eBay wouldn't have had any buyers left if they didn't start doing more about the fraud because buyer trust was being eroded quick.
Also I'v been doing this a long time. Years ago it was common for items to take over 24 hours to index. So the 6 hours it's been recently is relatively fast compared to the old days. Also they've at least made it so that once your items do index they get into the "Newly listed" section which in the old days didn't happen. We'd all like to see them get back to their really fast index times and I think that may happen over time but they're still working on getting the fraud systems put in place so that they can catch the hackers and fraudsters quickly and give a fast index.