You can get the information out of iCrew but it is a slow, difficult, error prone and extremely tedious task to manually calculate the exact hours you were present in what cities and figure out how much per diem you were paid and how much you were actually eligible for under the IRS guidelines.
Delta does not make this process convenient at all. Many many mouse clicks and lots of time with a calculator to do something a computer can do in nanoseconds.

Flightline and Pro-Diem have developed highly specialized software that is able to run scripts on Delta's mainframe and pull all that data out in just a few seconds and come up with the 3 or 4 critical numbers that we need to file our taxes. Then they sell us our own numbers for $50.

Delta's programmers could obviously do the same thing without too much effort but I guess this falls under the category of "what are you willing to give up for that".