I did some tests but couldn't reproduce these two issues. Advanced Reengineering worked for me on heavy units; maybe the problem was caused by the targeted unit instead of the Engineer-mod...
Walkers had regular accuracy as well in my test. I suppose the AI used the Shock and Awe doctrine to increase accuracy for explosive weapons.
Walkers had regular accuracy as well in my test. I suppose the AI used the Shock and Awe doctrine to increase accuracy for explosive weapons.