Hey Tenno,
I wanted to share a bit of a background design change that will happen with this Mod, namely that the ammo refund will scale with the ranking. As mentioned in the OP here, there is little reason to rank up the Mod, as it keeps the fire rate low, and still refunds all of the ammo. Pablo has reviewed reactions to this and feels that it's wrong to have unranked Mods being better than Ranked, so we are going to change this.
To keep this in line with other Mods, that ammo refund will now scale with the rank, meaning that you will get the full usage of the Mod when it is leveled. You should see this change in a coming hotfix, but we wanted to give you a heads up since you’ve put work into the research here and to let you know it is changing.
As for the other issues you have found, we will be looking at the bugs you have pointed out. Thanks for the build info!