Novolog 70/30 mix flexpen

I take insulin shots to control my Type 1 diabetes. I have asked my dr for a prescription for the flexpen. She provided it and gave me 2 sample pens. I read the pamplet inside and it states that after opening the pen should be discarded after 14 days. However the pen contains 100 units of insulin. That amount, when given in a vial, lasts me a month. The pamplet says that it can not be refridgerated after opening. My question is if I purchase the flexpen am I essentially throwing money away on the unused insulin? Are any of this type flexpen prefilled with less than 100 units of insulin? I am not willing to waste any insulin so I will not fill the prescription if I have to discard half the insulin.

Each flexpen actually contains 300 units of insulin, where each vial contains 1000 units. Both are U100 strength. You should get 5 flexpens per prescription for a total of 1500 units per month, which is actually more insulin than you get in a vial. Each 300-unit pen has a 14-day life once you take it out of the fridge where you have only 28 days total with the vial, whether you’ve used it all or not. So for many people, the flexpens save money on insulin because they throw less away. If you use 21 units or more per day, you won’t waste any insulin with a flexpen (where if you use less than 33 units per day you waste insulin from a vial), and you won’t have to refill your script as often as you do with a vial.