Comp XE270S experiences?

That sounds like the #20-246-4 cam that had 'variable' duration.
The adv duration can be changed by 10 degrees by changing the lash from 0.015" - 0.030".

So you have some adjustment you can play with.

Yes^^^this! I have tried it as tight as .014/.016" hot and as loose as .024/.026" hot and it does make a slight noticeable difference.