So I pull out a spreadsheet and begin working on a plan for the most efficent level up plan and I think I caught a problem.
I am going to start at the top and go backwards...
At level 75 in Arcane there are only two Recipes (Con +5 Str +5). Since there is nothing higher you have to save crafting those shards as long as possible. Assuming Maximum XP in crafting those Shards (at level 74) is 895 which according to the DDO Wiki would be enough points to level, however when you start moving backwards throught the list, with only 1 or 2 recipes available ...
Getting the maximum XP in each level between level 68 and 75 my math indicates you will be short some 250 or so XP points in Arcane. This of course takes into account the drop in XP for doing things below you level and not having things above your level. Of course this will be made worse by people making those shards at lower levels to level before hand.
Elemental, Divine and Arcane will be the order of difficulty from short the most XP to closest to having enough XP.
My a slight addition to my spreadsheet
For Level 68 through 75 you will be some 12 to 17 crafted shards short.
Maybe my spreadsheet isn't correct, but....