I had to give up the Progessive when the feedstore quit carrying it. I went with Purina's Enrich 32 and their Amplify fat supplement. They appear to be pretty comparable when you look at the labels. I do like the ration balancer feeding.
Are you looking to totally replace the PN? As in, you're looking to make your own ration balancer at a lower cost?
My "ration balancer" is a vit/min supplement by Dynamite (a mix of their 2 vit/min products actually) and added Tri-Amino from Uckele. That gets added to however many extra calories each horse needs. For the boys, there is no need, so I use a cup or beet pulp or a-pellets or oats or whatever I'm feeding the mare at the moment, as their mixer.
______________________________ The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET