Garageband recording music

I have been using Garageband which came with my iMac. Garageband 10.1.1 and imac OSX 10.9.5 at present. For years I have had a problem when recording. Using a keyboard midi, every digital note on every track is represented with another note behind it. In other words, If I click a note and drag it up or down, a duplicate note is revealed. No big deal I guess unless I want to change the velocity of a note (or all notes on a track) because the underlying duplicate remains the same velocity. It is maddening to be editing 10 or twelve tracks and having to make sure every note is addressed, those in front, and those behind the note you see. This can't be right. But I can't find anyone on forums who knows what I'm talking about. I even made an appointment with the Genius Bar in the next city (Tampa).. (I'm in St. Petersburg) boxed up my big iMac, lugged it across the parking lot, into International Mall, waited, only to be told by the genius guy and the manager that they didn't know much about Garageband, and the 'Garageband Guy' was not in that day. There is a lot of good stuff in Garageband and I'm very familiar with the process. But I'm out of patience. Before I buy new software I want to know if anyone KNOWS the source of this problem. thanks You will see in the first photo a Garageband 'Grand Piano' track.. the notes displayed by green dashes. I want to change the velocity of the one I'm pointing to.. say from 123 to 85. After changing the velocity.. the note still sounds the same. Why? Because behind it was a duplicate note with the velocity unchanged. And this goes for every midi note played. You will see in the next photo I clicked on the note and drug it down a half step. The bright one is the one underneath. I've tried several keyboards. Compressors and limiters only do so much; at least the ones in Garageband. They modify the tone as well which is horrible because Garageband has such great sounding instruments.