what it comes down to is are you happy. yes your fish are a bit stunted, but I have seen worse. they may not reach dinner plate size or be perfectly shaped, but if your ok with 4-5" fish then don't worry about it. you need to adjust your maintenence. wc's are your fishes best friend. you can't change too much water. the only way to get around this is to buy adults.but even they need more wc's than most other species. before spending anymore money, make sure you are going to commit to the care that these fish need. discus are not for eveyone. there are many beautiful species that are less demanding.
very good reply. i too thought about discus in the past, but like u just said the xtra work/time they need, its not for me i went with angles as a 2nd choice,even tho discus are my fav im just too lazy to keep them ,had about 2 years morning when my angles pasted, now i got sds seems i like the disk shape