Thanks, Wade.  I understand perfectly how the so-called "locks" (not really locking) work and have been using the Celestron OAG for several years.  It works well and I get excellent star shapes.  That is not the problem.  Now that I run through the entire night, there is the occasion when on meridian flip, there are no good guide stars for PHD2 as very few are present in the OAG FOV.  The Optec SMFFS is the best accessory I have ever bought for the Edge and the Optec locking knobs really tighten down the primary.  I've gone months with great success imaging throughout the night with the exception I mentioned above.