I've tried several things and discovered the following:
1. When I take ObjectDick out of my startup sequence my system boots in normal time (about 13 seconds - my boot drive is a Samsung 840Pro SSD.)
2. When I start ObjectDock after booting without it auto-starting it takes 17.4 seconds for the dock (I have only 1) to show up. This seems like a long time and I haven't investigated what's going on during this time. I'll do more on this and report back what I find.
3. After starting ObjectDock, if I close it and then restart it, the dock appears almost immediately.
So my preliminary conclusion is that ObjectDock has to do something special the first times it start after a system boot. Perhaps it is looking at disk drive catalogs - my system has 2 SSD's and 2 HDD's - but this is just a guess right now.