I'm leaning this way myself. If the stylus on your DI is long enough to reach the lifter cup, pull the rocker shafts and and pushrods and let it sit for a while. The DI wont put hardly any pressure on the lifters and they should stabilize enought to give you a close enough reading to see if a lobe is going flat or not. With that said, if you had a wiped lobe you'd be getting some racket out of it any way. Cam lobes generally don't just wear a little. When they start to go, they go.