I haven't used the camcalc app myself but I have seen similar issues with cam profiles from plans. Maybe related, maybe not, but one thing you may want to check is tangency between the arcs (assuming they are arcs). Depending on what parameters are predefined vs. what are resultant to satisfy defined parameters, there may be slight variations to the curve shapes and/or intercept positions. Some CAD programs provide some visual indication of fully defined vs. partially defined, but I suspect you know that already.
Another issue I have come across is: the cam profile can be fully defined, but when you overlay the profile of a cutter at certain points, it may 'dig into' a neighboring area as a function of the cutter profile itself (say a large diameter ball EM on a small cam). Its the same issue a cam lifter following a cam profile but yielding different open/close position than the cam because it sees tangency on its flank before or after the actual start/end position of the cam. An easy way to visualize in CAD is divide up the cam curve by N segments & overlay the cutter on tangent points. If it undercuts neighboring area, you know something needs to be corrected. Hope this makes sense.