I’ve been seeing different versions of Futura Medium; some with very tall ascenders, and some with not so tall ascenders. This goes back to metal versions and continues into the digital realm. Which is what Renner intended? Does the Renner book address this?
Here’s tall one
http://www.adobe.com/type/browser/F/P_046/F_FUTU-10005000.html
And a sample of CAPS vs lc ascenders which are not so tall
http://store.bitstream.com/testdrive.php?handle=573&text=CAPSbdfhklt&size=36&View+Text%21.x=48&View+Text%21.y=12