Hi Dennis,
Thanks for the congrats, surprised me a year ago.
Don't know if this helps found it on the Software Bisque link below, Sky6 allows use of both.
http://www.bisque.com/tom/minorplanets/occult.asp
"there is only a difference of 0.18 arc seconds comparing the IOTA updated elements to the elements found in the MPCORB.DAT file from the Minor Planet Center or 0.17 arc seconds comparing the Lowell Observatory ASTORB.DAT elements to the IOTA provided."
PeterM.