I get way more side-drops doing items 5-10lvls under the item lvl compared to doing them at the same lvl or above.

Vouch

I've had more drops doing wells 5-10 levels below the item level. I.E. Level 35's at 25 ect

Just my experience, the side drops for sure are better.

I like welling lvl 55 items at lvl 1 with a high prof char