I wait until fermentation is winding down to add the simple sugars. The yeast will be able to do their job better if you have them work on the more complex malt sugars first, then let them cruise through the simple stuff afterward.
Interesting. With an OG of 1.083 and a FG of 1.010, I had to change my attenuation of WLP500 to 88% from 75%. White Lab's lists its attenuation at 75-80%. I guess that's where my confusion comes in. Is attenuation dependent on the pitch rate?