Fudster - now I can really appreciate your frustration.
A lot of factories are just factories. They can put stuff together, but are not always good at trouble shooting or fixing after the fact. I'm sure I'm not telling you anything new, and of course this is true with many gun factories unfortunately. Or it may just be that particular day or person who happened to have tried to fix your gun at the time.
That is why I used the word "mechanic", not gunsmith. There is a difference. You need someone who really knows 1911's inside and out. Even though you have a LDA, you do not have a trigger problem, but a feeding problem. So a good mechanic can fix it. That is if the feeding ramp has not been screwed up already or such.
Ask around in your area for a good one. If you are not satisfied, go for a nationally known big name. You may have a long wait, but it seems that you are not short of guns.
MIke Bay in Tulsa is tops, Jim Clark - Louisiana, Wilson Combat, AK, Tim Lafrance- CA.
Look in American Handgunner and in the back many are listed that are in the top 100 .
Bottom line - that gun should shoot anything! Don't settle for less.
Reinz