This is not true for me. I just tested again to make sure that I'm not mistaken. I saved my game and loaded it twice to play in two different tournaments in the same week.
Exp points before first match: 66
Exp points after first win: 74 // This was the 2nd round because of my ranking.
Exp points before first match: 60
Exp points after first win: 76 // This was the 1st round in the main draw.
Is this supposed to be this way? I'm confused now because in the documentation it says that I should get between 10 to 20 points for my wins but I only got 8 points when I played in the ATP 250 event.
Also can these values be changed with Mods?