Hey tombola.
The problem is that matlab views a string as a row of ascii values. For example, if you have a date like '01/01/2000', this is viewed as [48 49 47 48 49 47 50 48 48 48]. This is precisely why you get a 100*10 matrix. The cell format views the string '01/01/2000' as a single "object", so if you try size(cell) it will give [100 1]. But the string format is different. If you need to work with the string form, convert inside of the specific function you are using, i.e. instead of having C as the cell and M=cell2mat(C), try f(cell2mat(C(i)) where f is your function and i the current index.
BTW, if you want to see this in action, just try '01/01/2000'+1-1 in the command window.
