How much time does putting an item inside a Bag of Holding take when you are fighting?

In the Bag of Holding’s (Dungeon Master’s Guide pag. 248) description it is stated:

Retrieving a specific item from a bag of holding is a move action — unless the bag contains more than an ordinary backpack would hold, in which case retrieving a specific item is a full-round action.

I am wondering how much time is required to put an item inside the bag while you are engaged in a combat encounter. Should it be considered as a move action as well? Should it be a free action if the item is small enough?

I have found this question that is almost the same as this one: How long does it take to place an item in a Bag of Holding or Portable Hole?

The only thing that has not been made clear is: does the item’s size influence the time I must spend to put something inside the bag?

Ex: Does a rod take more time than a ring? What about an halberd and a sword?