i am going with what has been said. 1200 sqft and two systems sounds like over sized and not albe to remove enough moisture and inproper drainage
the smelk of smoke may be the moisture building up on the motor windings and burning off, You will be replacing a motor soon
forget any fix for now
have a man-j load calulation done. Find out for sure how much cooling is needed for you condo. Then make an inteligent dicision about fixing the problem once and for all
you may find the new system you just had put in is big enough to do the intire condo and just some duct modifacations are needed to make it work
IMO forget about wat has been done and start at the begining Man-j load calc.
you can do your own by hitting the calc marker at the top of the page here. works great and is easy to do