Using the new HSM Advisor v0.4 I'v found some strange behavior while Modifying an End Mills' Helix angle.
Starting with a saved tool (solid end mill), if you select "edit tool geometry" & then change the helix angle you'll see the "Feed" field change (in the "Result" area), but only slightly. Then if you try entering different helix angle values to see the effect on the "Results" - the "Feed" field stops responding to the the newly entered "Helix Angle"... until you type the original "Helix Angle" value back in & then the Results seem to start updating again - correctly (you can then continue to try new helix angles & the results seem to continue to update).
The problem seems to be repeatable... Mainly a question for Zero_Divide, can you reproduce this problem with those steps?