Frame Score Chart for mature cattle

Anyone know where I can find a chart for mature cattle frame scores?  The charts on here, and everywhere else only take them to 21 months... - and I know the cattle will continue growing well after that stage of life...  It has a formula for calculating, but I can't seem to get it straight...  I suppose I need to find a different calculator that goes a few more decimal places, but I think it would still get me pretty close. 

I have a coming 3 y.o bull that stands 58", and a second calf heifer that stands 59"  Those are my 2 main concerns...  Just curious to see how big they are... 

Try this link to the Angus Association web site;

http://www.angus.org/Performance/AHIR/PerfFrameScore.aspx

It goes to 48 months of age. 

thank you, that will work!!