Here is what the documentation gives us:
vars.gameModeCounter controls the percentage of tickets compared to normal. 100 = 100% of normal tickets for that game mode / map combo.
vars.gameModeCounter is meant to be "clamped" between 75% and 125% on ranked servers.
vars.gameModeCounter is meant to be "locked" at 100% on Normal or Hardcore servers.
If you have been able to change your Ranked Normal or Ranked Hardcore server to more than 100% normal tickets in the past, DICE see this as a bug to be fixed.