I have a Sammic 310 but have never used the gas flush capability so I am sorry but I can't help assess that function for you. I didn't buy my Sammic for that but hearing the cost of the 'add-on' for other machines, I guess I am glad mine already has it so I won't have to reinvest down the line should I need it. However, the base machine is great - I love it. My only issue is that I probably don't use it often enough to justify the initial cost. I would say it is built like a 'brick ****house' if that kind of language were allowed here. Not much 'learning curve' for a novice either (so 'user controls' are pretty simple in my opinion). Mine is equipped to do retort bags (which was a priority for me when I purchased this unit).
Sounds as though you got a great deal on your MiniPack though so you will probably be further ahead in the long run even buying the extra capability than I bought at full price.
