Not trying to say what you were told isn't true. Howards does use a Landis LT1VE CNC cam grinder which makes grinding unique lobe profiles much easier than grinding cams manually on a Berco with actual physical masters. But I find it highly unlikely given the evidence I'm looking at.
After studying the majority of the Hughes cams, I can find the corresponding lobe in the Howards FM .904 lobe list. It looks like Hughes just rounds the Howards lobe up to the next .001 of an inch from what I'm seeing. If Howards has a .5876 lift lobe Hughes calls it a .588. Again not saying what you were told isn't true, but if there is a legit difference it is virtually nothing.