DeeDee can tell you exactly how much of a dog's diet should be fruits and/or veggies.
According to all the integrative Dr's and other raw feeding "specialists" that promote veg/fruit, they should get approximately 25-30% V&F of the whole meal, with fruits being 5-10% of that 25-30%. They digest puree better than whole fruits and veg pieces.
So a meal with F&V should be about 70-75% of the meat, bone, and organs. It's easy enough to use a kitchen scale to get these proportions. Just measure 5/8 to 3/4 an ounce of meat products to 1/4 to 3/8 ounce fruit and veg puree.
From what I've seen, all of the pre-mixes resemble formulations of "regular" foods like kibble instead of a raw diet so that they can claim "balanced and complete" by AAFCO standards. They might not have AAFCO seals, but they can say they follow the guidelines. So, yes. In my mind it's unbalanced to mix it the way they say it should be.
When I use the DR. Harvey's on the road, they get the kind with the meat already in it, and we feed only 1 of their 2 daily meals with it. But we're still not feeding it for long-term, so if it's unbalanced compared to the way we normally feed, it's not going to hurt them.