Mixing Instant Milk and Cow’s Milk?

Hi, my daughter is turning one in three weeks and I am concerned about when we want to go out, normally we take the instant Kendamil Follow on Milk at the moment and I’ve seen that they do a Toddler Instant Follow on Milk and thought this might be easier to take out than Cow’s Milk.

So my question is can I give my daughter Cow’s milk when we are at home and then if we are out for more than 3/4 hours can I use the Kendamil Instant Toddler milk or is it a bad idea to mix them?

Thanks for advance.