Definition of "overstuffing"

I have taken many an old sofa to pieces to find the understuffing was marsh hay, with a heavy over-stuffing of cotton, with no edge, but simply plain tufting.

1892, The Furniture Gazette‎, page 224

To remedy this, additional stuffing is pushed up under the overstuffing so as to crowd it out and fill up all hollows.

1914, John Wesley Stephenson, Furniture Upholstering: A Practical Handbook for the Upholsterer‎

Always use a layer of wadding or cotton overstuffing to make the work smooth.

1920, Furniture Manufacturer and Artisan‎, volume 19, page 49