Mystirious13 asked me some questions about the exp system and since it had no real meaning I thought of this:
Every time you reach the second lvl you can pay 200 DGA points for a re-test or just wait the 1 month period but if you take the re-test by reaching the next lvl and paying the points the 1 month period will start from the re-test you took last so the payed re-test.
The 200 DGA points will go to the tester who tested you.