Just a quick guess, I believe your net mineral interest is a function of the percentage of ownership interest you have in the total 160 acres. (ie. other people also own percentage interests as well) If I did the math correctly you have a 8.33% interest of the whole and others have 91.67%
This means if the lease is $350/acre you get $29.16*350 or alternatively 350 for 13.33 acres, both of which are $4,665.50. as your share of the bonus.
Also, mine was much further west and north (SW of Plentywood) and we were only offered $300 about 6 months ago for a 5 year lease, also with an "new" unknown LLC. When I asked it to be limited to a 3 year and release lease only upon receipt of cash, they declined to modify. I am waiting for someone else to come along at the moment, so you do risk loosing a deal sometimes, but then you don't know what might have happened had you accepted.
I've heard 3/16th is good royalty percentage, (but as the previous poster reported some are getting 20%) (3/16th is 18.75%) but you need to review the whole lease for other terms like how much for shut in wells and the like. If you don't understand these things you should have it reviewed by an attorney. Also, be careful with getting payment in escrow and not just a promise to pay later. If you give them a signed lease and then this LLC doesn't pay, they may have already signed over your lease to someone else and then you are left trying to sue to get your money from a bankrupt LLC speculator and trying void your lease as against a party claiming to be a good faith buyer innocent of the fraud by the other party LLC.
Your location is I believe in the heart of new active development closer to the ND border, go here to find what's happening around you: