Using your way to save data, there would be thousands of blocks data without any order. Finding specific data would be slow. For instance searching one block as below. There is 2 possible situation for year, 12 for month, 32 for day, 4 for gamemode, 3 for faction and 20 for rank.
Day: 3.6.2014Gamemode: NormalFaction: TerroristRank: 5
If it was arranged, finding data would be fast. There would be fewer options.
Server should only look 73 different situation. If they weren't arranged, it would be 184320. Arranged is more than 25x faster.
If it isn't possible to arranged data by date in .xml, should I use folders and many .xml files to make it arranged?