Tax form should be simple for the individual. I am currently dealing with the IRS saying I owe nearly 10k from 2014 when I sold stock I had bought but not sold for many years (never made a profit) because they do not know where I got money from in 2003. It was an inheritance and I gave them the insurance policy numbers, death certificate and they want to me to fill out more forms. They really need a form that says for inheritance. Going on 3 months now as they are slow to respond. Hopefully here good news this month from them....
The more complex the code, the more holes there are going to be in how it is administered. As you have found out, with the particular chain of transactions that the IRS is looking at, but not very wisely.