i've read through a lot of books and documentation regarding the added complexity of grids in data entry as used in a parent/child relationship (say, in an invoice).. is it better and easier to "mimic" the functionality of grids?

what i have in mind is for the given example, an invoice... say there needs to be quantity, unit, product id, unit price and total price columns... instead of using 5 columns in the grid, i could instead create a visual object comprising of say 5 text boxes (placed side by side, as if to mimic a detail line in a grid), this object will then be placed as a single column in the grid... that way, data validation can be done within the given detail line (since its an object by itself).. when the user needs to add a new detail line, a shortcut key or a command can just insert a new line (same class as that of the 5 textboxes side by side..) ?

is this a good way to implement parent/child data entry?