AddParameter method does not add in first column of datatable

[alpha1]

Hi,
If am using Datatable's AddParamter method, it adds the column not in place of first column "A" but adds it to next column. Eg,

Code:

Datatable.GetSheet(2).AddParameter "username","Ritika"        Datatable.GetSheet(2).AddParameter "pwd","hello"
wait  4

Should't it change first column name as "username". It is adding second column of datasheet as "username" . Pls see screenshot attached.