There are many factors that determine the rated capacity of any lift trucks beyond simple mathematical calculations of inch pound ratings, etc., etc. Other factors that determine the capacity are:

1. Amount of mast tilt
2. Physical limits of: a.) mast & carriage bearings b). Tilt cylinder strength, c.) Tire compounds & tire sizes d.) fork section (W &T) as well as length. & type (std. taper or full taper) used, e.) limitations of any attachment, f.) lift cylinder column strength.

Best advise let the manufacturer do the work & the lawyers won't get more $$$$.