You claimed you were using tropical coordinates to create your charts. Most public ephemerides are published in sidereal coordinates. You would have to translate from one system to another to get an accurate chart, or else there will be errors. I do not know what software program you are using, so I cannot comment on the accuracy. In addition, if you are using software to generate birth charts, how do you know the programmer knew what they were doing? You are simply taking their word that they are using the algorithms they are claiming to use. Unless you can generate a chart manually, you are simply relying on someone else's math, which gets you right back to square one in terms of determining accuracy.
I am going to go out on a limb here and claim that you are not the best person to be judging claims of astrologers, as I am not sure you know enough about the field.