Custom User Controls - Correct Size With User Choice

I have some custom user controls in my .net winforms program that do not display correctly when the user has selected larger text size. This setting:

My controls look like this:
Instead of like this:

The bill to area and ship to area are both custom controls. I don't know if this is contributing to the problem but I do have code in each to scale the phone/fax areas to stretch nicely, like this code from the bill to control,

Private Sub panFaxPhone_Resize(sender As Object, e As System.EventArgs) Handles panFaxPhone.Resize
panFax.Width = (panFaxPhone.Width / 2) - 1
panPhone.Width = (panFaxPhone.Width / 2) - 1
panFax.Left = panFaxPhone.Width - panFax.Width
End Sub

How can I get my controls to size correctly while still respecting the users choice for larger text (I don't want to just set the AutoScaleMode to None)? After playing with this for a long time it seems to be a problem with anchors in the child controls. See this below image, the inner black box is the control with its border turned on, the text boxes (like name) are anchored left and right and should stretch to fill the control, but don't.