The reason why it was the Qiao family and not the Xu family who made bids at first was because the Qiao family were flourishing for the past two years.
If the Qiao family appeared as though they were determined to win, then many people would give up their fight. On the other hand, since the Xu family asked for such a favor, they would save a large sum of money.
If Han Ruchu wanted Qiao family's help even after the way she treated Qiao Anhao... Don't count on it!
To make the Qiao family's aid seem less conspicuous, Father Qiao deliberately made two counter bids after Han Ruchu's bids.