TW/TWU Question on Twistweight

dave t

Hoping you can offer some insight about the twistweight table on TWU. How is this calculated? Are individual frames measured somehow? Or is there a formula?

I'm a little confused as I'm trying to compare an older version of a racquet to a newer one (Pacific X Force to Pacific BX2/BXT X Force). On your table, the X Force is 10.7 and the BX2 X Force is 13.21. Since the specs on these two racquets are basically identical - I'm wondering how the twistweights are so different? I customize my racquets and have an idea about my target specs - but I'm worried that using my modifications on my old racquet (which address stability and plow) would make the new one less maneuverable as the twistweight is significantly higher. Any insight? Thanks.