Even though the intent of the GIRM is to have Catholics celebrate the liturgy more uniformly, it has been implemented differently throughout the US. In my parish (and most in the Archdiocese of Detroit, if not all) we have been instructed to stand from the beginning of the distribution of Holy Communion until the door of the tabernacle is closed. When people from other dioceses visit it is very obvious by the way they look around confusedly when everyone around them is standing while they kneel. (lots of visitors recently because of First Communions)
I wish the GIRM had been implemented uniformly.
'thann