Technology Firearms and semi-automatic property

[Velkyn]

Is there official word on how the semi-automatic property interacts with iterative attacks? My understanding of the RAW is that a firearm with the property (text below) would provide two attacks at -2 normally, three attacks at -6 if you have Rapid Shot, and potentially a fourth attack at -6 with a Haste effect.

However, when I equipped a Rifle with the automatic property (which also supports semi-automatic mode) on my character in Hero Lab, it shows the standard iterative attack progression.

Is Hero Lab right? Am I misunderstanding the RAW? Or is there FAQ or other developer commentary on this topic?

PFSRD wrote:

Semi-Automatic: A semi-automatic weapon normally fires one shot as an attack. However, the user can take a full-attack action to fire twice, as if using the Rapid Shot feat (including taking a -2 penalty on all attacks). If the wielder has the Rapid Shot feat, she can use the additional shot from that as well, but the penalty for all shots fired in that round increases to -6.

[Coolwasabi]

Seems like using the Semi-Automatic during a turn is like using rapid shot. You take a -2 penalty on all of your attacks during a full attack but make an additional one at your highest bab (haste functions as normal).

However if you also have the rapid shot feat, you can instead take a -6 penalty on all your attacks during a full attack action, but make an additional 2 at your highest bab instead of additional 1 as above.