A parallel planar weight sensing device includes an accessory mounting bracket with an upper portion and a lower portion. Part of the accessory mounting bracket extends around a crossmember that also has an upper portion and a lower portion. Affixed to the upper portion of the crossmember is a first load cell while a second load cell is affixed to the lower portion of the crossmember. The upper portion of the accessory mounting bracket is affixed to the first load cell while the lower portion is affixed to the second load cell. An accessory, such as a shelf or hook, may be attached to the accessory mounting bracket and used to stow items. As the load on the accessory changes, such as due to a pick or place of items, a total weight change may be determined by summing the output from the load cells.