The converter shouldn't be locked up...you'll have to adjust your apply/release tables.
When you're giving it >30% throttle at 1300~1600 rpm and the converter is still locked up, you're going to put a lot of load on your motor. With an aftermarket camshaft that doesn't have the low-end grunt the stocker had, it's just too much sometimes. That's why you're seeing KR IMO. What you need to do is command the converter to unlock in those low rpm, high load situations. I posted an Excel worksheet somewhere on here a while back to help visualize the shifts along with the lockup. Try using that...
http://forum.efilive.com/showthread.php?t=5876