Eh 8 PS on a 5 riding horse isn't going to be much more damage than 7 PS and me on a courser. If anything I'd think I would do more damage at full speed. And the heavy lance is still pretty terrible unless you're hitting another cavalry or someone with low armor and not running in the same direction as you.
Tommy (don't think he plays much anymore) wears light armor, no helmet and only has his courser and heavy lance at +3. Don't think he has any other looms. And I'm not positive but I think he might be level 34 (possibly, might only be 33). For damage output, there's just no comparison between a heavy lance and a lance. I'd rather use a great lance than a heavy lance.